Information on Gemstones

by : teahupoo

When precious stones are found in mines, they don't look half as dazzling as they should look. Gems are finely cut, shaped and polished to give it that mesmerizing stunning and impressive look. The method of cutting the stone is known as gem cutting or lapidary. This process was started in the early 1300s in Venice. Later in the 1400s this method was used in Paris and Bruges. There are four basic styles of gem cutting, namely tumbling, faceting and carving. The precious stones should be cut so well that they mirror and reflect the light that falls on them. If the gem has not been cut or polished well, it destroys the beauty and the shine of the stone. For example, an alluring diamond, if not polished and cut well, will not be as valuable, rich or worthy compared to a well polished diamond.

The gem cutter or a lapidary, also known as lapidarist begins the process of lapidary by sawing the gem. The gem from the mine is first cleaned with oil or water, to remove the residues present on the stone. The stone is then sawed with a thin circular blade. One can use different sizes of blades, depending on the size of the stone. Sawing helps remove all the debris and chunks of mud stuck to the stone. The second step is grinding the stone.

Grinding is usually done with silicon carbide wheels or diamond-impregnated wheels, which is used to give shape to the gemstone to a desired rough form, called a preform. The third step is sanding which removes the scratches and dents caused by grinding. Sanding is a very delicate fine process, which is similar to grinding. If the stone needs to be flat at one end, then the stone goes through a process called lapping.

Laps are made of iron or steel, to flatten one side of the stone. Then stone is then polished, to create a mirror like effect. Polishing makes the stone so clear and dazzling that it shines. Polishing agents like tin oxide, aluminum oxide, ferric oxide and so on are used. Cloth, leather, wood, can also be used for polishing. The next process is cabochon. The gem is smoothly rounded and polished on top, and either flattened or slightly rounded on the bottom. This is usually done to opaque or transparent stone.

Transparent stones are also faceted. The stone is flattened at on the sides symmetrically and the entire surface is polished thoroughly, making it shine. The stone is then dopped on a metal dopstick, and later sanded and polished on a lap. Water or any liquid is used to clean the stone. A well faceted stone acts like a mirror, reflecting the light that falls on it, thus making it shine.