Gem Faceting / Cutting

[TooMuchInformation]

Alright, not too sure if this is the right forum for this question or not (didn''t find any other ones that seems particularly more appropriate), so if I''m in the wrong place, let me know and I''ll move my post elsewhere.

I''m looking to find someone that goes gem faceting / cutting. Wondering what tools they use, how they went about learning, and how difficult the process is to learn.

After purchasing an engagement ring for my now fiance, I''m totally obsessed with gems of all sorts; I just can''t read / learn enough about them!

 

[TooMuchInformation]

Furthermore, thanks very much for your information. How long have you been considering this as a hobby? I've only been interested for a little while (maybe a month?), but long enough to understand some of the terms that you're throwing around.

I guess one of my biggest questions would be how hard is faceting to do? I'm not interested in faceting diamonds (who has that much money to throw around!), but semi-precious and eventually precious stones would be totally fun to collect, analyze, and cut for fun. But, can anyone do this? How hard is it to learn?

I'm planning on dropping by a guild here in town (Calgary, Alberta), and I think they offer live demonstrations and such, which will be really neat to see.

 

[beryl]

. I am here at request of Garry Holloway.
. I have been cutting gems since early 70's. I have cut for fun and for profit.

. There is very little profit potential since you are competing with native cutters. The only area of significant income that I found is in re-cutting damaged stones for local jewelers. Interesting story: I had agreed to recut a large damaged amethyst for my son (a jeweler) for $25 but kept putting it off. While in a Brazilian mining town, he gave it to a local cutter, who did it, while we had lunch, for 28¢!

. There are many types of gem-cutting - cabochons, carvings, etc. My 'specialty' was carving - little animals, cameos, flowers, etc., but I was also noted for special cabochons with optical phenomena (several articles in Lapidary Journal, late 70's, and one coming out soon in Russian Gemmology Bulletin). In 1975 I won the EFMLS Lapidary Award (best score, all categories), having performed in the 'Mixed Lapidary' category. To get an extra point for another type, I bought a faceting attachment for my cabochon machine, then later a facetring machine (as a dealer, my cost was less).

. Each type of lapidary offers/requires something different. Carving requires the most artistic skill and dexterity. Intarsia (fitted color areas - like mosaic) is extremely difficult and requires great knowledge of stones and their polishing characteristics. Cabbing requires good manual control/technique. Faceting is done by machine and requires the least skill; I wrote an article for Rock & Gem magazine that began with "Faceting is boring."

. There are many makes of faceting machines but they consist basically of two types: mast-type and platform-type. Most are mast-type; I have used 3 different ones briefly and gave up on them...
--- Mast-type machines are inherently troublesome; because of deflections, and angular motion; they require great skill, adjustment, and patience to do a good job. Common types are Lee, Graves, MDR, Facette, Ultra-Tec, etc. Many of these require a 45° attachment to cut the table = another source of trouble.
--- Platform-type machines are best but least common in US = Raytech-Shaw, Imahashi, and a few others. Totally different concept - the stone is held in a tripod which rests on a platform; the platform is raised and lowered to bring the stone against the lap for controlled depth of cut, so there is no change in angle = one less variable to control! Best of all, you can lift up the tripod and turn it over, bring it to a light to inspect progress, eyc., without disturbing any settings!

. This year I joined the US Faceter's Guild, via USGF FacetersList in YahooGroups, hoping to share some tips on optics and cutting ovals which were not well-received in DiamondTalk. I was astonished at what I found there - people still having problems 'we' solved decades ago and blind leading blind. Most of the problems are due to the use of mast-type machines and lack of knowledge about dopping and lapping/polishing.

. There are many books available, advising about methods and/or providing diagrams for many cuts. There are also computer programs which enable you to design your own cuts and analyze light paths through them. I was fortunate to learn the right ways over the shoulder of a master and never used a diagram from a book. These new hobbyists are spending $$$$ for digital readouts, etc., because the books and/or programs are giving them degrees to 2- and 3- decimal places; I watched one diddle back-and-forth all by itself as the machine sat there and responded to motions in the room! THIS IS ABSURD!

. None of this is necessary. Cut your main facets according to visual protractor (± 0.1°), then adjust the machine to cut the others to fit - you don't even need to know the angles. It can be fun; it need not be difficult; people tend to make it so.
. KEEP IT SIMPLE.

 

[TooMuchInformation]

That's great that you've been cutting since the 70's; thanks very much for taking the time to answer my questions. People like you make this board an outstanding forum to learn.

Now, when you say there is "very little profit potential", I just want you to clarify a bit. I don't want to do this to make money, or as a full time business or anything of the sort. will it still be possible for me to obtain rough stones, facet them, and sell them for (much) more than I obtained the rough for? Are there any good examples of what a 20 carat rough chunk of Amethyst will cost and what it can be sold for after it's been faceted well (and chopped down to 3 - 6 carats)? Again, I don't want to do this for the profit, but I would like to know that the time that's put into faceting rough has an impact on the price of the finished product.

Carving sounds very interesting, however, it also sounds as though it requires a lot of skill and talent that I don't think I have.

Although I'm sure faceting will get boring at some point, I would assume that it would take you a bit of practice before hand. Would you say that some people would be happy faceting and not progressing on from there? I'd love to be able to do more intracate types of work, but if there's one thing that I've learnt about some really cool hobbies, it's that they take a lot more skill than I think!

I'm really happy that you've meantioned "Platform-type" faceting machines, because up until this point, I've never heard of them. I'll do some more research on them for sure, because all I had heard about to this point was how great machines like the Facetron were.

Can you recommend any books or other reading material that might help me on my way to understanding how faceting works?

Thanks again so much for all your help!

 

[beryl]

. Attached cropped photo of my Raytech-Shaw faceter. Factory has stopped making them but I think will have them made by a subcontractor. Some are available used; folks on USFG FacetersList advertize to buy/sell them. Additional features will be shown on subsequent photos. Imahashi machine is very similar. AVOID MAST-TYPE MACHINES.
. It is unlikely that you will find buyers for stones you cut. The market is not interested in colored stones or in quality of cutting. As described - I was a trophy-winner and my only income was by repairing damaged stones. In resetting them I broke some prongs and learned how to fix them - then I made as much money as time would allow - repairing jewelry - and that is how Harding Jewelers (AGS) began (see www.hardings.net). My son travels the world buying gems and making fine jewelry - not one domestic-cut stone in the lot.
. There are many books. I never used one but might recommend "Faceting for Amateurs" by Glenn & Martha Vargas, 2nd Ed. 1977 (they published themselves). They also have a companion book "Diagrams for Faceters"; I have never used one. I can send you scan copies of Raytech Faceters Manual, which tells you almost all you need to know in a few pages. Note that I never used these: I learned fundamentals from a master by asking a few questions and the rest was common sense; don't let people complicate it for you.

 

[beryl]

. LAP - In the above photo (Fig.1), the lap is to the lower left, rotated by a variable-speed motor about a vertical spindle. For rough-cutting I use diamond boart rolled into a copper lap with a ball-bearing. For final cutting, and polishing most stones I use polycrystalline diamond spray on a typemetal lap, using WD-40 as a rinse. It is imperative to have the lap radially scored so that particles have a place to drop out of the way so that they don't scratch the gem and so that the rinse can flush them away. Scoring is done by rolling radial groves with a glass-cutter; this not only removes no metal but raises the edges of the grooves, making them appear deeper to the particles. If you understand the logic of this, you will know how silly most modern 'solutions' are. I see the same old questions being asked and answered incorrectly all the time. For final polish of a few soft I may use cerium oxide or aluminum oxide on a radially-scored laminated-phenolic lap (also known as Bakelite, kunstharze-hartgewebe, etc.).
. My own special trick is a groove halfway out the typemetal lap, with fine-cut (prepolish) diamond on the outer half and polishing diamond inside = 2 laps in one - just move the stone from one to the other without any changes = less time, less chance for error.

. PLATFORM - At lower right in Fig. 1 (above) is a platform on which the tripod handpiece rests. This is on a post which swivels in a long bearing in the base of the machine, and is raised or lowered by turning a large wheel under the platform (which apparently is a nut on a threaded O.D. of the column). You adjust depth of cut by raising/lowering the platform as the stone meets the lap. You can put the tripod anywhere on the platform to contact the lap wherever you wish (lapping direction is often important); you cannot do this easily with most mast-type machines. You swivel the platform to oscillate the stone on the surface of the lap.

 

[beryl]

. Above, in Fig.2, you can see the the protractor for setting the slope (inclination) of the facets. This is simply visual and the best you can expect is ± 0.1°, but that's as good as you need; anything more recise is silly. Having set the slope at the protractor and the depth at the platform, you cut a series of identical facets by lifting the handpiece and rotating the index wheel to the appropriate notches.
. For a stantard round-brilliant you only need a 32-tooth wheel:
- mains at 4,8,12,16,20,24,28,32
- stars at 2,6,10,14,18,22,26,30
- breaks at 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31.
. There are various wheels available; 80-tooth shown is rarely used; generally 120 is max. I make my own for ovals.
. You can do all this using only one hand; I have set it on floor next to sofa while watching a movie (but made a wrong index by inattention while watching a beach-party movie).

 

[beryl]

. Figure 3 shows the handpiece turned over to examine the stone. You can take it ti a better light, examine it with a loupe, or show a friend - then go right back to work: no settings are disturbed. Think of this when looking at machines.

. Sometimes a lap gets worn and it is necessary to refinish it so it is perfectly flat. I do this by replacing the dop with a lathe cutting-tool and swinging it, like a stone on the lap. Then I re-groove the lap.
. It is important to always clean the lap between uses. I use WD-40 with a paper towel, wiping radially to clean out the grooves.
. Oils form paste with cutting 'swarf' (powdered particles of the stone); these cling to the surface of the lap and cause the stone to glide above the abrasive that is supposed-to cut it. Flushing 'oils' like WD-40 do not do this; they keep the surface clear so the abrasive can do its work better and faster. In the micro-finishing business we called these fluids 'rinses', not 'coolants' or 'lubricants', because it is what they do (I was fortunate to work in some industries which used principles I could carry-over to gem-cutting).

. Good luck and THINK SIMPLE LOGIC.