LAPIDARY GUILD April 2018 Issue Beginner Issue Where did gem cutting Issue No 1 * November 2016 get it’s start? by Gerald Wykoff, CSM GG Where did gem cutting get it’s start? 2 em cutting, or lapidary, most The breakage provided random Guide to Gem Cutting Terms 3 Gcertainly got its start as an fragments, but ultimately offshoot of mundane everyday experimentation demonstrat- activities. A stone may have fallen ed that breakage could also be Gemstone Orientation For 9 into a fire where the heat caused it achieved with some semblance to break or flake. Perhaps a sharp of control. Beginners edge resulted. This same knowledge of relative Certainly, flint and other hard hardness led to bruting, the shap- Lapidary Fundamentals: 11 stone possess sharp edges, but a ing of a gem specimen by rubbing blade-like cutting edge on a newly one mineral against another Cabochon Cutting flaked piece of rock suggested harder mineral. The slow and some very interesting possibilities. tedious practice of bruting was used for centuries until more Rock Tumbling: 17 In prehistoric times, man refined techniques were intro- hammered tools from stone, duced. Given the early date, Directions for Turning Rough Rocks into presumably smacking one stone historians are reluctant to Beautiful Tumbled Stones against another. He scratched attribute anything quite so intel- and chiseled out symbols and lectual as an understanding of primitive writings on hard rock cleavages. It was satisfactory and cave walls – and gradually that the breaking, chipping, or Artist Corner: Featuring Keith Cler 21 learned the great secret: some flaking of a stone could be stones are harder than others and disciplined…made to occur in de- therefore they are more capable sired directions and depth. How to Identify Unpolished Agates 23 of inflicting scratches on other less hard stones.From this very basic Later perhaps, someone viewed understanding, drilling and bruting these same stone fragments from became possible. a more abstract perspective. They viewed the unusual configuration, Drilling, one of the first of the texture, or coloring of a piece lapidary arts, traces its roots back of stone or mineral crystal, and almost 1,000,000 years ago. Prim- began to contemplate the possible itive peoples learned that rocks alterations of a stone for artistic or could be broken or fractured. adornment purposes. Tumbling Carving The simplest form of gem cutting is tumbling. Rough Carving is the most challenging of the lapidary Guide to Gem Cutting Terms gem material is put in a tumbler, a revolving barrel arts. There are very few recognized experts in the field. To succeed at gem carving, you do with abrasives. Progressively finer abrasives are used need a distinctive artistic sense and a thorough by Donald Clark, CSM IMG until the gem obtains a polish. This process closely understanding of the principles of lapidary. resembles what happens to rocks in a stream or on More so than wood or metal, working with gem the beach. However, polish levels are much high- material presents definite limits to what can be apidary is the art of working in stone. However, the word is usually used only in reference er. Tumbling is ideal for children and a great family done and the skill needed to do it. to working with small gem materials, not large objects like Michelangelo’s statues. There pastime. (It’s a great way to work stones collected on L family vacations or rock hunting). It’s easy and There are several types of carving. One of the are four basic styles of gem cutting: tumbling, cabbing, faceting, and carving. (There are also a requires minimal equipment. Plus, the results are best known forms is cameo. These are usually number of ways of assembling gem materials to make jewelry, ornamental objects, and mo- sensational! You can also purchase inexpensive cut from sea shells or agates but can be carved saic-like patterns. You can learn about these techniques from this article on assembled gem- from almost any material. Cabochons are often settings and turn tumbled stones into jewelry pieces. carved. If the design is cut into the top of a cab, stones). This guide will cover gem cutting terms from the four basic fields. ouY can learn more They make wonderful homemade gifts about these techniques in the Fundamentals of Lapidary series. it’s called an intaglio or relief carving. If the design is carved on the back, it’s a reverse inta- glio. Some carvings are not designed to be used in jewelry. They are cut simply for their beauty. These are classed as stand alone carvings. Cabbing Cabbing or cabochon cutting is probably the most common form of gem cutting. Cabochons or “cabs” are gems that are cut with a flat bottom and a curved or domed top. If you’ve seen opal or turquoise jewelry, you’ve probably seen cabs. Cutting cabs can be profitable. Depending on the material they’re cut from, cabochons can have sig- nificant resale value. This can make cabbing a very rewarding hobby, especially if you’re cutting materials you’ve found yourself. Cabbing is more complex than tumbling, and a cabbing machine is a bit more expensive, but you can become proficient with a little practice. A word of warning: cabochon cutting can be highly addictive! Faceting Styles Faceting Faceting is the cutting style with the greatest profit Brilliant Cut Ceylon Cut potential. If you can imagine a diamond in a typical engagement ring, you’re likely visualizing a faceted Examine the round brilliant diagram below left. It has The Ceylon cut has a step cut pavilion and a brilliant gem. The surface of that diamond is covered with triangular and kite shaped facets. This style is called a cut crown. This is an ancient technique still used in Sri several geometrically arranged, flat surfaces. Each of brilliant cut. Lanka today. Modern computer studies have shown these flat surfaces is called a facet. (Some questions, that the reverse, a step cut crown over a brilliant cut like gems, can also be “multifaceted”). Step Cut pavilion, will often produce the greatest brilliance. The purpose of faceting is to bring out the brilliance Barion Cut of a gem. Light entering the stone is reflected off the A step cut features rectangular shaped facets neatly arranged, one on top of the other. The emerald cut, bottom facets and returned to the viewer. Brilliance The Barion cut was developed by South African dia- shouldn’t be confused with dispersion or fire, which a cut-cornered rectangle shape shown below right, is mond cutter Basil Watermeyer. Essentially, it places is the multicolored flashes you see coming out of the most common example of a step cut. a round brilliant pavilion into a fancy shaped gem. diamonds and some other gems. It usually has a step cut crown as well. This usually results in far greater brilliance than other methods. Gems are faceted by faceters on faceting machines. Interestingly, Mr. Watermeyer invented this cut just There are many kinds of faceting machines. If you before the advent of computer ray tracing programs. want to facet gems for fun or profit, prepare to make a significant investment in equipment. When facet- The round brilliant pavilion, compared to other ing, more so than the other gem cutting styles, your pavilion shapes, offers greater light discipline inside equipment quality will affect both your results and the gem. Barion cuts display a fountain of light effect your enjoyment. that is quite striking! There are also many kinds of faceters. Faceting is an art, but you don’t need some esoteric Rose Cut “artistic sense” to be good at it. Machinists, engineers, and those with a knack for math often excel at faceting. Many faceters are semi-professionals. They sell enough gems to support their hobby or A gem with a faceted top and a cabbed flat bottom is supplement their income. For those interested in collecting or investing in gems, this is by far the called a rose cut. Occasionally you’ll see a gem with a most practical gem cutting style to learn. The price of rough and labor is almost always less than the faceted pavilion and a domed crown, but this is not a wholesale price of the finished gem. standard method of cutting. There are two basic styles of faceting: brilliant cuts and step cuts. These styles are often combined. Named Cuts Some cuts combine faceting and cabbing. There are standard, well-recognized cuts like round brilliants and emerald cuts. Most faceted gems are simply called by their shape. However, there are “Although you can become good at many variations within each shape. A triangular gem faceting with a minimum of experience, can have many or few facets, much or little brilliance and scintillation, etc. you’ll never run out of new challenges.” Portuguese Cut Curved Facets The Portuguese cut has several tiers of facets, which Flat facets are not the only technique available to create a wonderful display of light. It has more today’s gem cutters. scintillation than almost any other cut. As you can see from the picture, it requires many facets and requires Fantasy Cut considerable labor. These factors, in addition to the A fantasy cut is a popular style of faceting. This tech- fact that the rough must have greater than normal nique uses large pavilion facets. Some simple grooves depth, make this cut something that is used only are used, which are mirrored throughout the pavilion. occasionally. This ametrine is an excellent example of a fantasy cut gem. Some cuts have no name Concave Facets at all.