POLISHING CARVING AND ENGRAVING

PRECIOUS METALS AND GEMS usually I massive, microcrystalline stones and organics-can be worked by polishing, carving, or engraving. Polishing is the oldest form of fashioning. Carving produces three-dimensional objects by cutting them from a larger mass of material. Engraved images are made by scratching out lines or holes, or by cutting away to leave a raised image. Carving and engraving require tools harder than the material being worked.




Polishing

The shine given to the surface of a stone - either by rubbing it with grit or powder, or against another stone - is its polish. Dark- colored gemstones and those that are translucent or opaque, for instance opal and turquoise, are often polished rather than faceted, as are organic gems. 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.

Carving

Carving usually refers to the cutting of decorative objects from a larger mass. Stones as hard as 7 on the Mohs' scale were carved in Ancient Egypt, Babylonia, and China. Impure corundum (emery) was used for carving and engraving in India; nowadays a hand-held chisel or turning machine is used. Popular stones for carving include serpentine, Blue John, malachite, azurite, rhodonite, and rhodochrosite

 CHINESE CARVING Carving of gemstones in China dates back to the Neolithic period. The most prized material was imported nephrite jade, and decoratice objects like this model pagoda are still made.

Engraving

 Engraving usually refers to the decoration of the surface of a gemstone by the excavation (scratching out) of lines, holes, or trenches with a sharp instrument, known as a graver or turin. Of all engraved objects, cameos and intaglios are perhaps the most popular. A cameo is a design (often a human profile) in flat relief, around which the background has been cut away. In an intaglio it is the subject, not the background, that is cut away, creating a negative image that may be used as a seal in clay or wax. Intaglios were particuiarly popular with the Ancient Greeks and Romans, and are still prized by collectors.

GOLD ENGRAVING

The surface of gold and other precious metals used in jewellery may be decorated with intricate patterns, using a hand-held chisel called a graver. Engraved gemstones gained prominence in Europe in the Renaissance period. During the Elizabethan period in Britain cameo portraits were often given as gifts, particulariy among the nobility. All through the ages, layered stones have been used for cameos or intaglios, with onyx and sardonyx particulariy popular. Other gems suitable for engraving include rock crystal, amethyst, citrine, beryl, peridot, garnet, lapis lazuli, and hematite, as well as organic materials such as ivory and jet.

MODERN DESIGNS 

This citrine prism, with its clean, architectural lines and exquisite engraving, demonstrates the flair and craftmanship of modern designers. Its maker, Bernd Munsteiner, uses conventional cuts to create classic modern jewels akin to pieces of sculpture. Bernd Munsteiner is one of many artists working in Idar-Oberstein in Germany. Together with Hong Kong, Idar- Oberstein is considered to be one of the most important centres for gemstones today.