Gemstones
Gemstones are naturally occurring crystalline forms of mineral, they are desirable for their beauty, value, rarity and durable enough to last for generations.
There are more than 40 popular gem varieties and many rarer collector gemstones. Some gemstone varieties have been treasured since before history began and others were only discovered recently, although they are all a wonder of nature.
Cutting
Lapidary is the art of working in stone. For some reason though, it is only applied to working with small, gem materials and is not extended to large objects, like Michangelo's statues.
There are four basic styles of gem cutting:tumbling, cabbing, faceting and carving.
TUMBLING
The simplest form of gem cutting is tumbling. This is where the rough material is put in a revolving barrel with abrasives. Progressively finer abrasives are used, until a polish is obtained. This process closely resembles what happens to rocks in a stream or on the beach, except that the level of polish is much higher.
CABOCHON CUTTING
As it is commonly known, cutting cabs, is probably the most common form of gem cutting. Cabs are gems that are cut with a flat bottom and a curved or domed top.
Cabs have distinct resale value, based on the material they are cut from and their cutting can be profitable. This makes for an excellent, indoor hobby. It is especially enjoyable if you are cutting materials you have found yourself.
FACETING
Faceting is the style of cutting that has the greatest profit potential. Examples of faceted stones are diamonds; the surface of a diamond is covered with several geometrically arranged, flat surfaces. Each of these flat surfaces is called a facet. The gem is faceted, by a faceter on a faceting machine.
This is also where we get the expression, "a multifaceted question." The purpose of faceting is to bring out the brilliance of a gem. That is where the light entering the stone is reflected off the bottom facets and returned to the viewer. Brilliance should not be confused with dispersion or fires, which are the multicolored flashes you see coming out of diamonds and some other gems.
CARVING
Carving is the most challenging of the lapidary styles and there are very few recognized experts in the field. To be successful, one must have a distinctive artistic sense and a thorough understanding of the principles of lapidary. Unlike working in wood or metal, the materials present definite limits as to what can be done.
There are several types of carving. One of the best known is cameo. These are usually cut from sea shells or agates, but they can be carved from almost any material.
If a design is cut into the top, it is called an intaglio, or a relief carving. If the design is carved on the back, it is a reverse intaglio.
Diamond cutter's shop, eighteenth century, in which the diamond-cutting mill is operated by "man-power". Published in the Universal Magazine of Knowledge and Pleasure, by John Hinton, England, July, 1749
List Of Gems
Below is a list of the worlds most common gemstone varieties.
