Officers and Appointed Staff United States Faceters sharing information

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2 US.F.G. Newsetter Vo. 8 No. Apri, 1997 Officers and Appointed Staff President... Raph Mathewson Secretary... Eva Mathewson 3551 NE Surf Dr., Lincon City OR ewiis@ewiston.com Vice President Chares L. Moon Myrte Court, Arcata CA cmoon@sprintmai.com Treasurer... Don Dunn Renown Rd., Dayton OH, ddunndtn@ao.com Membership.. Jean Marr P.O. Box 1815, Kernersvie NC mystixs@nr.inti.net Editor... Robert Strickand Earyway Dr., Austin TX rstrick@compuserve.com NOTCE: The opinions expressed in the newsetter are those of the editor, contributing members, or quoted authors, and do not necessariy represent the United States Faceters Guid or its membership. This newsetter is for the express purpose of sharing information with the members and other faceting Guids, and has no intent to show preference to, or cause damage to any product manufacturer or commercia company. Correspondence concerning the content of the newsetter shoud be sent to the Editor (see officers, above). Exchange buetins and newsetters shoud aso be sent to the Editor. N THS SSUE USFGNews... 3 SEND US YOUR E-MAL ADDRESS Membership Appication Form... 4 The Pan View Shape... 5 Since communication in the USFG is very difficut, Fred Van Sant due to our wide-spread membership, if you are a OMN and Breakpoint Methods... 6 USFG member and have e-mai capabiity, woud Fred Van Sant you pease send your e-mai address to our Vice President, Chares Moon, cmoon@sprintmai.com? Sunrise Cut... 7 A compete membership ist wi make necessary Fred Van Sant communications much more viabe! Moon wi OMN Standard Ova Briiants compie the addresses and distribute the ist to the Robert W. Strickand Mathewsons, Don Dun, Jean Marr and Robert Od Uncuttabe Revisited Strickand. Robert H. Long OMN Egg and Shied Robert W. Strickand The USFG N ewetter is a quartery pubication of Tips for Gemstone Microphotography 23 the United States F aceters Guid. t is deivered by first cass mai to a paid members of the Guid at the end of March, June, September, and December. The 1997 voume number is 7. Membership dues are $15 per year and are payabe to the USFG treasurer. Page2 Scott and Susan Wison What is a Tier? Fred Van Sant Preforming and Paviion Rough Shape Fred Van Sant Northwest nternat. Faceting Conference. 29

3 US.F. G. Newsetter Vo 8. No. 1 A pr i, 1998 Eedion Resuts Outgoing Secretary, Chares Moon has tabuated the baots, and they have been confirmed by Jean Marr. The resuts are: President Vice President Secretary Treasurer Membership Editor Editor Resigns Raph Mathewson Chares L. Moon Eva Mahewson Don Dunn Jean Marr Robert Strickand First off, thank you for your vote of confidence by reeecting me as your Editor. apoogize for not pubishing the December issue. t is with regret that announce that must resi gn as Editor. After numerous attempts to jugge my responsibiities to famiy, career, church, GemCad and this newsetter, find must give up something. Over the past three months, have come to the concusion that cannot both edit this newsetter and upgrade GemCad. For every one comment get about this newetter, get asked about ten times, "When wi GemCad for Windows be avaiabe?" have made much progress on this front the past few months, but it has been at the expense of this newsetter. Again, pease accept my apoogies for faiing to pubish the December issue. Dues Due? Check your maiing address abe for the date of your ast issue. Pease aso check your name and address for accuracy. Dues are $15 per year. Make check payabe to Don Dunn, USFG Treasurer (address on inside cover). f you are not yet a member, pease compete the appication on the back of this page and send it to Don Dunn ( address on inside cover) with your $15 check. Meetpoint Techniques Many thanks to Fred Van Sant for contributing severa artices. The first, entited "The Pan View Shape" (page 5) gives a summary of severa methods of meetpoint faceting that generate the girde outine (the pan view) in different ways. Next comes an artice that compares and contrasts the OMN method and the Breakpoint Method (page 6). Both of these techniques were introduced ast issue. n ast issue can be found the "Aternate Paviions for the Ova Checkers." These cuts are designed to generate the girde outine using the technique Fred has termed the Breakpoint Method. owe Fred an apoogy for pubishing these desi gn s without expaining the Breakpoint Method in more detai. Fred has come through again with an exceent artice expaining the Breakpoint Method. After you read Fred's artice, take another ook at his Ova Checkers in the ast issue. Fred's artice goes on to compare and contrast the Breakpoint and OMN Methods. Fred's "Sunrise'' (page 7) is a new Breakpoint design. Fred aso contributed "What is a Tier" (page 27) and "Preforming and Paviion Rough Shape" (page 28). More on the OMN Preforming Method Next comes my artice (page 8-13) showing step-bystep how to cut the paviion to my OMN Ovas (page 14-18) using the OMN Method. The artice goes on to compare the OMN technique and the Breakpoint Method on the same design. Bob Long has contributed a new version of his design, "Od Uncuttabe." Bob's "Od Uncuttabe Revisited," (pages 19-20) uses the OMN preform instead of the CAM preform of the origina. Unike the other OMN desi gn s in this and ast issues, in the "Od Uncuttabe Revisited" the OMN facets are temporary and are cut off by the other paviion facets. OMN Shied and OMN Egg As promised in the previous issue, have contributed OMN versions of a shied and egg cut briiant-stye. Both show how the OMN technique can create compicated outines simpy. Both desi gn s have a OMN facets cut at the same ange and mast-height! Tips for Gemstone Microphotography Scott and Susan Wison have contributed an exceent artice, page 23-27, on photographing your faceted gemstones, reprinted from the Juy-August 1997 issue of the New Mexico Facetor 's Guid Newsetter. Northwest nternationa Faceting Conference Rapidy Approaching! See pages 29 and foowing. Page3

4 US.F G. Newsetter UNTED STATES FACETERS GULD Appication for Membership The USFG is open to faceters everywhere. Our primary goa is to improve the art and science of faceting through our newsetter and correspondence. Our secondary goa is to improve competitions and competition rues, both in the U.S. and internationay. Officers are eected every two years for 2 year terms; 99e begins with new officers. ssues are voted on by mai. Members receive our Quartery Newsetter - usuay about 20 pages each, and the right to participate in the USFG activities. New members receive a copy of our Constitution upon request. Name Street Address Date Teephone City, State, Zip am a faceter --- am interested in becoming a faceter compete or have competed at the foowing eves: Junior Novice ntermediate Advanced Master do not wish to compete. have a dispay case 12 stones 20+ stones Educationa Other Which machine do you cut with? Do you cut commerciay? Deaer? Do you need hep with, or information about, your type of machine? Have you judged in competitions? nterested in judging? Have you given taks or written artices on faceting? Specia taents or interests to share? Encosed is my check for $15 (U.S.) for 1 year membership in USFG $16 (Canada), $19 (Overseas) MAKECHECKSPAYABLETODONDUNN MAi., TS FORM PLUS CHECK TO: Don Dunn, 993 Renown Rd. Beavercreek, OH Teephone: (937) Rev Page4

5 US.FG. Newsetter Vo 8. No. 1 Apri, 1998 ) The Pan View Shape Meet ine Preforming: After making A summary of stone shaping by Fred Van Sant the primary set of ECED girde facets, secondary girde facets are cut to meet the ines made by the The purpose of this artice is to bring primary set. See artice in USFG Newsetter, attention to the variety of methods by which stones September 1993, caed 11 Circuar Preforming 11 can be shaped. t is important that we know about Other non-circuar girde shaping is done these methods, and that they be named and de- by a combination of ECED facets and measurement.. scribed, for if they are not th rn when we begin Most common is measuring ength and width to cutting a design we may not see the easiest and best conform - the stone to the L/W of the design sheet. ways of cutting it. f we don 1 t have the idea of a method we wi not see it in the diagram. From Aso measuring girde facet engths can make the desired shape. persona experience can assert that the designer (8 PONT AT CULET: This starts with himsef may overook the best cutting sequence. a set of (at east 3) facets cut at the same ange and f the design aows ony one method, and that method wi cause too much waste of materia, positive stop to a point centered on the dop axis. The point made may be a Temporary Center Point you shoud ook for another design. But you shoud (TCP) or a Permanant Center Point (PCP). There not give up too easiy; it often happens that the are severa methods to be foowed: diagram sheet does not show a possibe ways of Cor ner.l.ocator Ange Method preforming, or even the best way. f you ike the design, study it cosey for other methods before giving up on it. (C.L.A.M ). Two sets of cuet facets are cut to a TCP. These create ines which intersect one or both sides of corner girde facets. Then girde The term 11Preforming" was originay used facets at 90 are cut to meet the comer ines. After to appy to the rough eimination of materia to obtain a shape approximating the finished stone shape. n faceting, the term has come to mean making a precise shape matching the one shown on a pan view on the diagram sheet. Since in some methods of cutting, the shape is not made unti the the shape is made the cuets are overcut and ost by faceting the permanent paviion facets. Sometimes designs have such ines connecting the cuet point to a comer, so the shape can be made in the same manner using facets that are permanent. paviion is amost or competey finished, the.qenterpoint Ange Method (C.A.M.): 11 Pre" in "Preform" seems inappropriate. So for this artice we are concerned with methods of making the fina shape of the stone. n genera, a shaping (or cutting) begins Cuet facets are cut at girde indexing to a TCP, using anges such that when the stone is 'rounded off at 90 using the same set of index numbers, the desired shape wi resut. either (A) at the girde with a set of 90 girde Omni: See next page. f a the outine facets, or (8) at a cuet point made by a set of facets points necessary to create the shape have, in the at a given ange. Both of these methods are based on pan view, straight ines connecting them to the two settings derived from the faceting machine-- 1) a constant ange, and 2) a constant dop arm position which resuts in equa Norma ntercepts cuet point, then the design can be preformed by the Omni Method. Breakpoint: See next page. Breakpoint for the facets cut. On vertica mast machines, and Omni adapt we to many modern designs with equa Norma intercepts are obtained by keeping steep barion break facets. R. Strickand 1 s Diamond the mast in a fixed ocation and having a positive stop for the swing of the dop arm. Checker Ova in the Mar-June issue is an exampe. Meet point: The outine shape deveops as (A) GRDLE PREFORMNG: n this the resut of cutting a the paviion facets. Sequencing method the shape is made first and directy, using varies with each design, but they a start an ange of 90 degrees. Before computer design from a Center Point. Sometimes considerabe upand-down entered the scene, the roed girde, which imitated cut diamonds, was popuar and showed up in mast adjustments are required. n Genera: A methods which start at the cuet many designs. With computed designs the faceted require the cutter to traverse the entire vertica girde made the design much easier to compute, made for an even-width girde, and aso for easier aignment after transfer-dopping the stone, so it dimension of the stone to arrive at the tabe, so there is a greater number of facets through which sma errors can accumuate than is the case where. has mosty repaced the roed- girde. an accurate girde is made first. Therefor, starting Girde Shaping begins with a set of ECED at the Center Point requires great accuracy on facets at 90. f cut on symmetrica index numbers the paviion meet points to make the outine as a circuar shape resuts, but any index numthe. bers may be used. precise as possibe. D Page5

6 US.F. G. Newsetter Vo 8. No. 1 Apri, 1998 NEWER METHODS OF MAKNG THE STONE'S SHAPE -- by Fred Van Sant Neither of these methods described beow is totay new. Both have been done before, but neither was seen as a GENERALMETHOD which coud appy to a variety of shapes unti Both pertain to the pa viion, which is to be cut first. Both are specia sequences of Meetpoint cutting. CAM, Omni, and Breakpoint can be mixed on the same stone.. THE OMN METHOD THE BREAKPONT METHOD SEQUENCE: 1. A set or sets of facets are cut to a Permanent Center Point (PCP). 2. A set of 90 girde facets is cut to make the size. of the stone. This creates the primary girde points for step three. 3. Remaining girde facets are cut in a meetpoint sequence, starting from primary girde points. The shape is now made, but the girde is not eve. FEATURES: The step 2 girde facets are cut to make points farthest from the stone center. The cuet point can be fina. There is a minimum of overcutting, ost materia, ost time, or mast movement. The primary girde points wi be at the fina girde eevation. The other girde facet points wi be coser to the cuet. The go 0 girde facets have different index numbers than the cuets; if they are the same it is a CAM preform. The Omni can work on a variety of shapes. On the pan view the ines from the cuet connect with points on the outine. Later overcutting (break facets, for exampe) may obscure this feature, but it is essentia to the Omni preform. SEQUENCE: 1. A set or sets of facets are cut to a Permanent Center Point. (PCP) 2. A set of go 0 girde facets is cut to make the size of th?tone. _This creates the primary girde points for step three. 3. A break facets are cut meetpoint, beginning at primary girde points. 4. Remaining 90 girdes are cut meetpoint using break facet indexing to make a eve girde ine. FEATURES: The step 2 girde facets are cut to make points farthest from the stone center. The cu et point can be fina. There is a minimum of materia oss, time oss, or mast movement. On the pan view of an OMN Preform the ines from the cuet meet points on the outine. The Breakpoint Method is free from this restriction, but the girdes must be cut on the same index numbers as the break facets if a eve girde is to be made. Breakpoint wi work on a variety of shapes. The Breakpoint method does make the pan view shape, but because the shape comes at the end of the sequence, it is not considered a preform method. Omni and Breakpoint Compared These methods are not reay new; what is new is our thinking about them and giving them a name to keep them in mind when either designing or ooking for the best way to cut an existing design. Certain types of designs end themseves to Omni and Breakpoint cutting: Cushion Trianges, Cushion Squares and Rectanges, and Ovas can often be cut by one of these methods, even if an Omni or Breakpoint sequence is not given. For both methods steps 1 and 2 are the same. Omni then chain-cuts the girdes; Breakpoint chain-cuts the break facets. Since most Omni designs wi have break fac::;ets which make a eve girde, there is often itte difference in the appearance of the paviion pan view. f points between cuet and break facets are foating, it cannot be cut Breakpoint, because in chaining the break facets, the points made are 4- facet points. Omni aows for such points to foat. Page6 f in the pan view a design has ines from the cuet which meet, or coud if extended meet, points on the outine, then it is possibe that the stone can be preformed by the Omni method, otherwise it cannot. f the intermediate points are 4-facet points, and the cuet ines coud meet points on the outine, then it might be cut either Omni OR Breakpoint. With Omni, step 3 makes the shape; with Breakpoint, step 4 makes the shape. f a the points on the outine can be made by cutting girde facets which meet ines from the cuet, then the design can be preformed by Omni. Lines which bend passing through the break facets indicate the paviion may be cut Breakpoint but not Omni; however, if such bending ines are not needed to make the shape, it may sti be cut Omni. For an Omni shape, it is essentia ony to have sufficient cuet-to-girde ines to make the shape.

7 US.FG. Newsetter Sunrise 96 ndex Gear Anges for R == 1.7+ Vo 8. No. Apri, 1998 Crown: 1. 4 at at at at at at at at at ndices 2,46,50,94. 6,42,54,90. 10,38,58, , 72. 7,4 1,55,89. 15,33,63,81. 3,45,51,93. 10,38,58,86. 18,30,66,78. w 96 L L/W = Tabe Area = 31,T TfW. =-.54 C/\N =.1634 PfW = t,5387 H/W = A/W =.2987 B/W =.4659 F/VV =.1305 VF =.3146 GVF = % 1 H p t T i Paviion nstructions 1. Cut set 1 to a PCP. 2. Cut sets 2,3,4,5 to meet the PCP. 3. Cut 2 at 90 at 24 and 72 to set ength. 4. Cut break facets 6,7,8 to meet as shown. 5. Cut girde facets at 90 starting at corner to make eve girde ine, using facets 6, 7,8 indices. Paviion: ndices 1. 4 at ,31,65, at ,38,58, at ,42,54, at ,46,50, at , at ,3 8,58, at ,42,54, at ,46,50,94. Desinged by Fred W. Van Sant A F Page 7 96

8 U.S.FG. Newsetter Vo 8. No. 1 Apri, 1998 OMN Standard Ova Briiants by Robert W. Strickand Severa shapes end themseves to easy cutting with the OMN Method, described in the ast issue. Cushions such as the cushion triange, square, and pentagon in the ast issue are ideay suited to the technique. Ovas are aso good candidates. Commercia settings for ova stones are avaiabe in numerous sizes. The different sizes have different ength-to-width ratios. The most common are 1.2:1, 1.25: 1, 1.33:1, 1.4:1, and 1.5:1. Some sizes fa in between, but most standard sizes are within a few percent of these ratios. have designed a series of ovas in these aspect ratios that take advantage of the OMN Method. See pages for the diagrams. These are the easiest ova briiants to cut that know of. The designs are found on pages Other uses for these ovas are in cutting a repacement stone for a setting or cutting to maximize yied for a piece of rough. A of these OMN Ovas have the same cutting sequence. The fattest two (1.2:1 and 1.25:1) are cut using an 80 index gear. The remaining are cut on the more common 96 index. As in the other OMN designs in the previous issue they have the foowing advantages: 1. A preform facets are kept ( and not cut off by subsequent facets). 2. The girde outine is estabished eary in the cutting sequence. f you ook carefuy at the diagrams you might note that the break facets don't quite meet up. This can easiy corrected during prepoish or even poish with a tiny change in ange. This probem is due to the unequay-spaced OMN facets that meet at the temporary center point. coud have incuded facets that cut off the OMN facets to fix the meets, but it hardy seemed worth the confusion that that woud introduce on the diagrams. The designs are for Topaz R. of 1.63 or higher. The cuet anges are beow the critica ange for quartz. You can adapt the designs to quartz by just omitting the itte cuet facets. The companion artice on pages 8-13 shows the paviion of one of these designs, the 1 :33 : 1 ratio, cut at each stage. For those of you that missed ast issue, it might aso serve as an introduction to the OMN technique. The artice goes on to compare the OMN Method to the Breakpoint Method. Showing the same design cut with the two methods reay shows the difference between the two techniques. Farewe Fine Facetors from Down Under From the North York Guid in Canada comes the sad news that Peter Coins of Austraia died of a massive heart attack ast month. Peter was one of the driving engines behind the 1200 member Austraian Faceting Guid during most of its history. He had been one of the founders of this organization, its President and as we the ong-time editor of Facet-Tak, its newsetter. At the time of his death, he was working on a book about faceting co-authored by John Broadfoot. Before his death, Peter Coins informed us by e-mai of the death of noted Austraian faceter Frank Dickson. Frank died of a severe heart attack December 9. Frank was 81. Peter wrote, "Severa USFG members have stayed at Cremore, Sydney, with Frank and his wife Noa on visits Down Under, and he was hed in very high regard. Frank was a member of severa nternationa Chaenge teams and was AFG faceting champion in 1988, the year he married Noa... He was one of our finest facetor-jeweers and won the jeweery section of our annua competition severa times." Frank was the winner of the Austraian nternationa Faceting Competition in Frank's eight stones entered in their Guid's 1997 Warwick Competition ost no points for poishing (160 out of 160) and ost ony 0.05 point for scratches (79.95 out of 80). Frank pioneered the use of Tefon-based "Super- Lube" ubricants. Page 8

9 US.F G. Newsetter Vo 8. No. 1 Apri, J.2 J. J.8 SDE t EHD - --L- - - J i t EHD ---L--- BOTT OH SDE 90 6 i ! i f END ---L--- BOTTON SDE BOTTON OMN OVAL --OMN SEQUENCE First we wi cut the design with the OMN Method as shown in the diagrams. The cutting sequence and appearance is the same with a of the OMN Ova s. Choose the diagram that best matches the egth-to-width ratio of your rough. This artice assumes a 1.33 to 1 ratio. The diagram for 1.33:1 is given for a 9 6 gear. The first step is to cut four of the Step 1 facets to a point After this your stone wi ook ike the top picture. These four facets meet at a temporary center point (TCP), and the remainder of the step 1 facets are cut at the same mast height and to this same TCP. B Next, we cut the step 2 facets to the same TCP. (This wi require a sight change in mast height.) The stone wi now ook ike the midde picture at the eft. Next we are ready to estabish the ength of the stone. f we want to cut the argest possibe stone from this design (assuming that the rough is at east as fat as the 1.33:1 ratio, that is, if our rough L/W measures ess than 1.33) then we meet the point indicated by the circe. We cut four girde facets : G The stone wi ook ike the bottom picture. We wi next cut step G2 to meet the indicated point. Page 9

10 US.F.G. Newsetter END - - -L <, i T END i ---L J.2 G J.' G2 Vo 8. No. 1 Apri, 1998 SDE 1 BOTTOM SDE BOTTOM SDE After cutting G2 G to the meet point indicated on the previous page, the resut is shown in the top picture at the eft. Note that the temporary girde is not eve. This is norma and is the main distinguishing characteristic of the OMN method. The meetpoint for next step G3 is indicated. The meetpoints for the remaining girde facets chain around the stone. G This resuts in the midde picture. Note that the fase girde ine is getting deeper. The girde outine is competed with the step G4 facets. G At this point, we have etabished the fina girde outine of our stone! A of the step 1 and step 2 facets are permanent facets. f we were cuting a CAM preform, these woud a be cut off ater. The eve of the fina girde ine starts where step 2 meets step G2. t is a good idea at this point to measure the amount of materia eft for the crown. f there is not enough to compete the crown, you might consider making a second pass around the girde to make a smaer stone or prepare to shorten the crown by tangent-ratio scaing. Next, change to the prepoish (1200 to 3000) ap and prepoish a facets. For a but the argest stones, the remainder of the paviion facets can be cut directy on the prepoish ap since they remove very itte materia. END ---L--- G4 BOTTON Page JO

11 U.S.F.G. Newsetter Vo 8. No. 1 Apri, 1998 = TŌP S , DE t END - -- L- - - T EN D L ' 01.' BOTTON SDE BOTTON SDE 1 The next step is to cut the barion facets that serve to eve the girde. The meet point for step 3 is shown in the bottom picture of the previous page Step 4 is cut to continue to chain the eve girde around the stone. t wi meet step the point indi cated in the top picture Step 5 finishes the eve girde. t is cut to the meet point indi cated in the midde picture f cutting in quartz or bery (R < 1.6) stop here! Steps 7 and 8 wi be beow the critica ange for quartz. The cutting sequences for the other aspect ratios are the same as for this design. BREAKPONT METHOD Now we can compare the OMN sequence above to the same des ign cut using the Breakpoint Method. Athough this design is better suited to the OMN Method, by cutting the same design using the Breakpoint Method, we can gain insight to the differences between the methods. The two sequences are exacty the same through the bottom of the first page where the girde facets G estabish the fina size of the stone. With the Breakpoint method, the barion facets are cut before the remaining girdes. These begin with step 3 and are cut to the same point indicated on the bottom picuture of the first page. END ---L--- BOTTON Page 11

12 US.F. G. Newsetter SDE Apri, 1998 After cutting step 3 (Breakpoint Method) END ---L BOTTOM SDE i i , ----t 1 END ---L--- 1 BOTTOM SDE BOTTOM your stone wi ook ike the top picture. The next set of barion facets chains to the indicated meetpoint The resu t is the midde picuture The ast barion facet chains to the indicated meetpoint The resut is the bottom picture Next we cut the remaining girde facets to eve the girde. The G2 barion facets meet the indicated point. This is the distinguishing feature of the Breakpoint Method. The high-ange break (or barion) facets chain around the stone. n this design note how the edges between the break facets ine up with the edges between the cuet facets. This is NOT typica of Breakpoint designs. n genera, with a Breakpoint design these edges wi not ine up. This gives the designer more fexibiity but is usuay of itte concern to the cutter. Note that with the OMN sequence, we woud have the fina girde outine after having cut the same number of facets as we have so far with the Breakpoint Method. n genera, the OMN Method gives the finished girde outine as soon as possibe in the cutting sequence. Page 12

13 U.S.FG. Newsetter 1 H END 1 H END ---L L t 1 G.' G.' G2 Vo 8. No. Apri, 1998 SDE BOTTOM SDE BOTTOM SDE 1 After cutting step G2 G to the meetpoint shown at the bottom of the previous page, the eve girde starts to work its way around the stone as shown in the top picture. The next set of girde facets G is cut to the point indicated in the top picture. The resut is the midde picture. See how the eve girde chains around the stone? The fina set of girdes G competes the eve girde. The resut is exacty the same as with the OMN Method. n this design, the OMN sequence is preferabe to the Breakpoint sequence since it generates the outine sooner and with fewer arge changes in mast height. So are there any advantages to the Breakpoint Method as compared to the OMN Method? The advantages are primariy to the designer and not the cutter. For a design to be cut with the OMN Method where the OMN facets are preserved, the edges between the barion facets must precisey ine up with the edges between the OMN facets. (The OMN facets in the "Od Uncuttabe Revisited" are cut off.) Athough these OMN ovas are better suited to the OMN than the Breakpoint Method, by comparing the same des ign cut with both methods, hope you have a better understanding of the differences between the two methods. END ---L--- G3 / G4 BOTTOM Page 13

14 US.FG. Newsetter Vo 8. No. 1 Apri, E --T-- OMN Ova 1.20:1 (OMOV1 20A.GEM) by Robert W. Strickand 3/13/98 T r C Anges for R.. = facets + 16 facets on girde = 85 2-fod, mirror-image symmetry 80 index L/W = T/W = T/L = P/W = C/W = H/W = (P+C) /W+0.02 = P/H = C/H = Vo./W A 3 = PAVLON TCP TCP G Estabish ength G OMN : Meet 1-2-G* G OMN : Meet 1-1-G2 G OMN : Meet 1-1-G Leve girde Meet Meet cuet Meet cuet CROWN A Leave some girde B Leve girde C D E Meet A-A at girde F Meet B-C at girde G Meet D-D at girde H Meet A-B-E-F J Meet C-D-F-G 0.00 Tabe *OMN preform is formed by steps 1-G4. The girde ine wi not be eve unti steps 3-5 are cut. Page 14

15 US.FG. Newsetter Vo 8. No. 1 Apri, r E T!!ii OMN Ova 1:1.25 (OMOV125A. GEM) by Robert W. Strickand 3/13/98 T r C Anges for R.. = facets + 16 facets on girde = 85 2-fod, mirror-image symmetry 80 index L/W = T/W = T/L = P/W = C/W = H/W = (P+C) /W+0.02 = P/H = C/H = Vo./W A 3 = PAVLON TCP TCP G Estabish ength G OMN : Meet 1-2-G* G OMN : Meet -2-G2 G OMN : Meet --G Leve girde Meet Meet cuet Meet cuet - CROWN A Leave some girde B Leve girde C D E Meet A-A at girde F Meet B-C at girde G Meet D-D at girde H Meet A-B-E-F J Meet C-D-F-G 0.00 Tabe *OMN preform is formed by steps 1-G4. The girde ine wi not be eve unti steps 3-5 are cut. Page 15

16 US.F G. Newsetter Vo 8. No. 1 Apri, E 96 T 6 ;, OMN Ova 1.33:1 (OMOV133A.GEM) by Robert W. Strickand 3/13/98 T r C Anges for R.. = facets + 16 facets on girde = 85 2-fod, mirror-image symmetry 96 index L/W = T/W = T/L = P/W C/W = H/W (P+C) /W+0.02 = P/H = C/H = Vo./W A 3 = PAVLON TCP TCP G Estabish ength G OMN : meet 1-2-G* G OMN : Meet 1-1-G2 G OMN : Meet 1-1-G Leve girde Meet Meet cuet Meet cuet CROWN A Leave some girde B Leve girde C D E Meet A-A at girde F Meet B-C at girde G Meet D-D at girde H Meet A-B-E-F J Meet C-D-F-G 0.00 Tabe *OMN preform is formed by steps 1-G4. The girde ine wi not be eve unti steps 3-5 are cut. Page 16

17 U.S.FG. Newsetter Vo 8. No. 1 Apri, E--T. _,,.. 1 OMN Ova 1.4 0:1 (OMOV140A. GEM) by Robert W. Strickand 3/13/98 Anges for R.. = facets + 16 facets on girde = fod, mirror-image symmetry 96 index L/W = T/W = T/L = P/W = C/W = T f C H/W = (P+C) /W+0.02 = P/H = C/H = Vo./W A 3 = PAVLON TCP TCP G Estabish ength G OMN : Meet 1-2-G* G OMN : Meet 1-1-G2 G OMN : Meet 1-1-G Leve girde Meet Meet cuet Meet cuet CROWN A Leave some girde B Leve girde C D E Meet A-A at girde F Meet B-C at girde G Meet D-D at girde H Meet A-B-E-F 'J Meet C-D-F-G 0.00 Tabe *OMN preform is formed by steps 1-G4. The girde ine wi not be eve unti steps 3-5 are cut. Page 17

18 U.S.F.G. Newsetter Vo 8. No. 1 Apri, E--T 6 - OMN Ova 1.5 0:1 (OMOV150A.GEM) by Robert W. Strickand 3/13 /98 T r C Anges for R.. = facets + 16 facets on girde = 85 2-fod, mirror- image symmetry 96 index L/W T/W = T/L = P/W = C/W = H/W (P+C) /W+0.02 = P/H = C/H = Vo. /W 3 = PAVLON TCP TCP G Estabish ength G OMN : Meet 1-2-G* G OMN : Meet 1-1-G2 G OMN : Meet 1-1-G Leve girde " " Meet Meet cuet Meet cuet CROWN A Leave some girde B Leve girde C " D E Meet A-A at girde F Meet B-C at girde G Meet D-D at girde H Meet A-B-E-F.J Meet C-D-F-G 0.00 Tabe *OMN preform is formed by steps 1-G4. The girde ine wi not be eve unti steps 3-5 are cut. Page 18

19 US.F G. Newsetter Vo 8. No. 1 Apri, 1998 Od Uncuttabe Revisited by Robert H. Long After deveoping the OMN preforming system, ooked for a good candidate for its appication. Since originay had so much troube cutting "Od Uncuttabe," that design seemed ike a good candidate. t turned out to be an exceent choice for repacing the origina CAM preform with an OMN preform. n designing the OMN preform, the comer facet having the hightest eevation ange in the "Od Uncuttabe" design was chosen as the starting point in the preform design. This turns out to be a genera rue of thumb in designing an OMN preform. t wi usuay provide the most efficient preform, since the starting facet in the OMN preform is aso one of the fina facets in the stone. The competed OMN preform is shown beow. With this prefom, a tiny remnant of one of the preforming facets ( ) wi remain when a the fina paviion facets are cut. This tiny remnant is shown highighted by circes in the next picture ( above right). A sight recutting of a the paviion facets, as wi occur with the pre-poish cutting step, shoud remove this preforming remnant. The presence of this ROUGH-CUT PAVLON SHOWNG PREFORM FACET REMNANT remnant of a preforming facet is an indication that the preform is the most efficient possibe. At the request of a reader, OMN preforms have been cacuated for Bribaro (02.128) and Ember (04.037). wi be happy to work on any other designs any readers may suggest. Contact me at: Robert H. Long th Ave. S.E. Mercer sand, WA E-mai: RHLong@msn.com WG1- - G3' < 96> 6 96 OMN Preform for Od Uncuttabe Revisited by Robert H. Long P PS P P P P G5 G6 G G G G GS G ndex L/W = C/W = Page 19

20 U.S.F.G. Newsetter Vo 8. No. 1 Apri, r 84 p m f 0 e :r Joi Od Uncuttabe Revisited with OMN Preform by R.H. Long C See attached instructions for more detaied preforming instructions..: Anges for R.. = facets + 20 facets on girde = fod, mirror-image symmetry 96 index L/W = T/W = T/L = P/W = C/W = H/W = (P+C) /W+0.02 = P/H = C/H = Vo./W A 3 = OMN PREFORM Girdes (G-G6) wi not make eve ine on the OMN preform. PAVLON CROWN G a G b G C G d GS e G f From preform g Meet corner h Leve girde i Leve girde j Leve girde k Leve girde Leve girde m Leve girde n Meet Meet p Meet q Cut to PCP r Meet Tabe Meet Page 20

21 U.S.F.G. Newsetter Vo 8. No. 1 Apri, E----'W-- OMN Egg Briiant (OMNEGG.GEM) by Robert W. Strickand 4/2/98 Anges for R.. = facets + 16 facets on girde = 87 1-fod, mirror- image symmetry 96 index L/W = T/W = T/L = P/W = C/W = H/W = (P+C) /W+0.02 = P/H = C/H = Vo./W A 3 = OMN 1 G G2 G3 G4 PREFORM (See page 28) Meet TCP Set size GS Meet 1-1-G G Chain rest G GB PAVLON CROWN a b C d e f g h i j k m n p q t 0.00 Tabe Page 21

22 US.F G. Newsetter Vo 8. No. 1 Apri, r 78 T C r W'--- OMN Shied (OMSHLD.GEM) by Robert W. Strickand 9/1/97 Anges for R.. = facets + 13 girdes = 68 mirror-image symmetry 96 index L/W = T/W = P/W = 0.5 C/W = H/W = (P+C) /W+0.02 = P/H = C/H = Vo./W A PAVLON G G G G GS G PCP Note Note Leve girde CROWN A B C D E F G H J K L M N p Q R T Tabe Breaks " t t " t Mains Stars Note 1. Facets G and G6 are cut at about the same mast height, so rough-in G (pointy end) and G6 (fat end) first to size the stone. Note 2. Steps 1-G6 comprise an OMN preform. The girde ine wi not be eve unti steps 2-6 are cut. See page 28. Page 22

23 US.F G. Newsetter Vo 8. No. 1 Apri, 1998 Tips for Gemstone Microphotography by Scott and Susan Wison From New Mexico Facetor's Guid Newsetter, Juy-August 97 NTRODUCTON Pick up any issue of the Journa Gems and Gemoogy and you wi see beautifu cose-up photographs of faceted gems. t is natura, and probaby correct, to presume that these photographs were taken with speciaized, expensive equipment and setups. We describe some techniques that obtain comparabe resuts with ordinary cameras, fim, and some inexpensive accessories. To take quaity gemstone photos requires consideration of the foowing aspects: 1. Camera, Lens, and Tripod 2. Fim 3. umination 4. Magnification 5. Stone preparation 6. Stone mounting and support 7. Exposure and Depth of Fied 8. Processing f one takes the time to consider each of these items, it is actuay quite easy to come up with exceent photographs of your stones. t is ceary not possibe to address these topics in compete detai in this forum, so for in-depth information you might want to consut a good book on the subject. We recommend Photographing Mineras, Fossis, and Lapidary Materias by Jeffrey Scovi (Geoscience Press, Tucson, AZ, SBN , about $40). This book covers ots of territory and is very readabe. t does not, however, contain some of the tricks we are about to offer! We' hit just some highights here. CAMERA AND LENS A 35mm SLR camera with through-the-ens (TTL) exposure metering is amost a necessity uness you are we versed in the intricacies of exposure cacuations. TTL metering makes it much easier to obtain a proper exposure. You' aso need a way to obtain magnifications so that your stone fis between 50% and 75% of the fied of view. This can be done in one of two ways: Cheap: Use your norma camera ens, but get some extension tubes from a camera store. These tubes, made speciay for each type of ens mount, space the ens from the camera body. This greaty increases the magnification. t aso reduces the amount of ight that gets in, resuting in onger exposures (not a major probem). More expensive: Get a macro ens for your camera. A pain macro wi give much better image quaity than the more common zoom-macro enses. Macro enses can be expensive though, so give a zoom-macro a try if you have one. We have used a Canon AE-1 body ( od technoogy by current standards) with the standard 50 mm ens and 50 mm extension tube and obtained good resuts. This combination gives sufficient magnification to fi 75% of the fied of view with a 10 mm stone. Make sure that you use a remote shutter reease. This is a itte cabe with an actuator on the end that attaches to the shutter reease on the camera. t aows you to reease the shutter without jigging the camera, and is essentia for obtaining sharp pictures. Use a tripod. Make sure it's rock soid. You may find it convenient to set up the tripod so that the camera points down at the comer of a tabe for your work. This ets you pace the amps on the tabe, aong with the stone mounting arrangement, whie keeping the tripod stabe on the foor. FLM Fim seection is a bag of worms. There are questions regarding coor baances (dayight vs. fash), speed, side vs. print, etc. For our purposes, we found that ordinary 200 ASA Kodacoor God print fim provides acceptabe resuts with toeraby ong exposures. You may need to experiment a bit d ep ending on the coor of your stone and your camera/ens/ighting setup. f you are using extension tubes to get magnification, you' have a difficut time getting enough ight on the Page 23

24 U.S.F. G. Newsetter Vo 8. No. 1 Apri, 1998 subject to use fim sower than 200 ASA. Stick with reasonaby fast fim to make your exposures easier to take. LLUMNATON Professiona minera photographers have a whoe array of ighting sources and arrangements at their disposa. They seect the ighting to highight aspects of the specimen being photographed, and often use a combination of a ight box (a box with a transucent top upon which the specimen rests, it from beow), direct ighting, and diffuse ighting. You might expect that some kind of ight that iuminates the stone from a points in a circe around the ens might produce good resuts. Such a ight is caed a ring ight and is used often in industria inspection. They generay don't do we for gemstone photography because they make the stone ook fat and ifeess. We found that a sma incandescent tabe amp with a non-patterned, white shade, and a bright Tensor-type ight are sufficient to get nice photos of faceted stones. Avoid fuorescent amps as they ficker on and off 120 times per second, faster than you can see, but often sufficient to confuse your camera's exposure meter. Fuorescent bubs aso have a different coor spectrum than tungsten incandescent bubs, and this may throw off the coor baance. f the amp has an adjustabe intensity, it is best to set the intensity near the maximum eve and eave it there, adjusting the amount of ight that fas on the stone by backing the ight away from the stone. The reason for eaving the power eve fixed is that the coor spectrum of the ight produced by the amp may change greaty depending on the power setting, and you want the coor spectrum to remain constant for a your exposures to preserve whatever coor baance you have avaiabe. The Tensor ight shoud in genera be very cose to the ens barre to get nice interna refections in the tone. Make sure that you don't start to heat up the ens though! The tabe amp can be moved around to provide some baance and overa iumination, perhaps highighting a specific interna refection or producing a peasing iumination gradient on the background. The exact iuminations setup is best determined essentiay by tria and error. Look through the viewfinder at your stone whie it is in the position for being photographed, and adjust the ights (use an assistant) unti you get peasing resuts. Pay attention to strong shadows ( either minimize them or use them creativey), highights within the stone, and hot spots (very strong, annoying refections from a facet). This takes time, but remember that the camera wi see exacty what you see in the viewfinder, so make the time investment. MAGNFCATON As mentioned above, you generay wi want a singe stone to span 50-75% of the fied of view. f you use too itte magnification, your stone wi be difficut to appreciate in the photo. Too much magnification starts to bring out imperfections in the stone and dust on the surface of the stone. Uness you are trying to photograph the incusions in your stone, don't push the magnification too far. High magnification aso brings out dust on the surface, and can aso reduce the depth of fied so much that it becomes impossibe to have the tabe and back facets in focus at the same time. STONE PREPARATON The crown and paviion of your stone must be absoutey cean. This incudes dust, which is a rea irritant in this type of photography. Use whatever magic recipe you customariy empoy to cean a stone. Use of ens tissue is recommended to move the stone to its mount and arrange it there. Use of goves is generay a waste of time due to the int and dust that is produced. Anti-static precautions may be hepfu to keep dust from setting on or near a freshy ceaned stone. Be especiay wary of tiny water spots that may appear when using typica 70% isopropy achoho to cean the stone. The acoho may evaporate, eaving the water behind as very tiny dropets. These dropets wi cause the surface to ook sighty fuzzy and wi cause the stone to ook ess briiant than it shoud. nstead, find some 91 % isopropy acoho. t shoud be avaiabe in we-stocked pharmacies. The reduced water content eiminates this probem. (As a side note, this can aso be a probem when cod <opping since the water dropet Page 24

25 US.F. G. Newsetter Vo 8. No. 1 Apri, 1998 steady hand for pacing the stone--make sure the stone can't fa on something hard if it fas off the needes) but the resuts are worth it! Take your time with the ighting. Try ots of variations in ight position and intensity whie ooking through the viewfinder. Don't forget about the background and possibe shadows that may fa on it and appear as out-of-focus bobs in your photo. You wi eventuay find a combination that is neary breathtaking! EXPOSURE AND DEPTH OF FELD Getting the exposure right can be a bit tricky. You want to accompish a number of things at the same time: 1. Getting the right amount of ight in to make the exposure. 2. Keeping the depth of focus ong enough to have the whoe stone (tabe down to paviion) in focus, but not enough for the background to be in focus. 3. Keeping the exposure short enough to avoid reciprocity faiure--this happens when you try to use the fim outside its design exposure imits, and shoudn't be a probem unti you start getting exposure of severa seconds (for ASA 200) or onger. The depth of fied is greaty infuenced by the aperture setting. A arge diameter aperture ( sma aperture number) wi give a short depth of fied, and a sma diameter aperture (arge aperture number) wi give a ong depth of fied. The depth of fied is the distance parae to the ens axis over which the subject wi be in focus. You wi have to pay with your setup to find the best aperture setting; we found that we needed about an '5.6 aperture to get the correct depth of fied. Note that on automatic cameras, you must find a way to k eep the aperture fixed and vary the exposure using the exposure time. Set the exposure time so that the camera thinks it has a ''norma" exposure. Often, this means that the TTL metering shoud indicate 5.6. Note that you may need to find out how your camera ''weights" the picture for its exposure cacuations and make appropriate adjustments. n genera, it is best to "bracket" your exposures by one stop. This means that you take a picture at one stop underexposed ( via the exposure time, not the aperture, to avoid changing the depth of fied), and one stop overexposed, as we as norma exposure. Keep a og so that you know what your exposure conditions were for each picture you take--this information is vitay important when you get your photos back and want to know which combination worked the best. When you snap a picture, make sure that the tabe and tripod are both steady. Use the remote shutter reease to genty take the picture. Make sure that the tabe and tripod aren't vibrating during the exposure, such as might be due to a nearby refrigerator, dishwasher, or overy interested pet. PROCESSNG Even if you do everything right, the processing can sti make the difference between success and faiure. The deveoping of the fim itsef is a simpe matter -the processor wi dip the fim in various chemicas according to a recipe from the manufacturer and that's about the end of it. The printing is where some additiona trickery needs to happen. First of a, avoid mai-in processing (as opposed to one-hour type service) at first. Mai-in processing is generay done fuy automaticay with no person ever coming into the oop. One-hour processing normay has a person sitting at the machine to make the exposures during printing. Find a processing center you can trust (and not go broke with) and tak to the operator who wi print your photos. Te them that your pictures are of a technica nature, not scenery, and that you may need them to adjust the "density." Suggest that they start out at "pus one density" and adjust further if necessary. The density is simiar to the exposure that you made with the camera, ony now the exposure is appied to the print, not the fim. You might aso want to te them what coors they shoud see, so they can baance the coor to some extent for you. Te them that you have bracketed the exposures and which ones are pus one and which are Page 25