Cutting and Polishing gemstones
The shine given to the surface of a stone -either by rubbing it with grit or powder, or against another stone – is its polish. It can also be said thet polishing is the systematically progressive reduction in the size of scratches until they are invisible to the naked eye.. Polishing of a gemstone is done by the use of very finely powdered abrasives such as corundum powder, tripoli, pumice, putty powder, etc. Each gem material requires special treatment to obtain the best results. It is here that most of the trade secrets apply. In general, the polishing powder should not be quite as hard as the material to be polished, else it may grind rather than polish. The material should be used with water or oil to give it a creamy consistency. Dark-coloured gemstones and those that are translucent or opaque, for instance opal and turquoise, are often polished rather than faceted, as they are organic gems. Opal, being a softer rock require treatment more like that accorded cut glass, and soft abrasive powders, such as pumice, suffice to polish them. They may be polished as beads or as flat pieces to be used in inlay work, or cut en cabochon with a smooth, rounded surface and usually a highly polished domed top and flat base. Gems which are transparent are normally faceted, a method which shows the optical properties of the stone’s interior to its best advantage by maximizing reflected light which is perceived by the viewer as sparkle. There are many commonly used shapes for faceted stones. For example, a rough diamond crystal is fashioned into a brilliant-cut. This is the most popular cut for this stone because it maximizes the gem’s naturally strong light dispersion. The craftsman, or lapidary, who cuts the stone aims to show its best features, taking into account its colour, clarity, and weight. The facets must be cut at the proper angles, which varies depending on the optical properties of the gem. If the angles are too steep or too shallow, the light will pass through and not be reflected back toward the viewer. There are several stages in the cutting of a gemstone, each of which may be carried out by a different expert.
Read more about how gemstones are polished, engraved and carved
By: Iris Dcosta
About the Author:
Iris Dcostawww.valuablestones.com
