The Meaning of Gemstone

A gemstone may be a rock, mineral, or even a petrified material that’s cut and polished to be used for making jewelry pieces. It may be even harvested like pearls or organic like amber, just as long as it has aesthetic appeal. In the old days, precious gemstones only referred to the Big Three: emeralds, sapphires, and rubies. Everything else was labeled as semi-precious gemstones.

Categories today, however, have been thankfully changed and widened to avoid further confusion.

The Ins and Outs of Lapidary

Lapidary refers to the process of cutting and polishing gemstones. Rough materials are left uncut and unpolished. Cobbed materials are referred to as fractured. Materials like silicon carbide and diamond, due to their hardness, are used for cutting gemstones in a progressive abrasion process. Compounds like aluminum and chromium oxide are, on the other hand, used for polishing gemstones.

Common cutting techniques include tumbling, drilling, polishing, lapping, sanding, grinding, and sawing. Cut gemstones are then polished into several forms such as sculptures, intaglios, cameos, mosaics, intarsias, inlays, spheres, beads, cabochons, and faceted stones.

Sawing The main tool used in sawing is a copper or steel blade with diamond grit on the edges. Water or oil is used to eliminate cutting debris and prevent the blade and stone from overheating.

Grinding Diamond-impregnated grinding wheels made of silicon carbide are used to grind gemstones and shape them into a pre-form. Liquid substance is also used to prevent both the stone and tool from overheating.

Sanding This process is similar to grinding but utilizes finer abrasives instead. It is often performed as a follow-up after grinding for removing scratches caused by the previous cutting technique. For round gemstones, a belt sander may be used in accompaniment to ensure smoother and rounder curves.

Lapping A lap, which is a flat disk that’s either vibrating or rotating, is used to create flat surfaces rather than round ones. The process however is similar to sanding and grinding.

Drilling This technique is used if the lapidarist wishes to create a hole through or in a gemstone. Drilling tools may be rotating or ultrasonic.

Tumbling A gemstone that’s placed in a rotating barrel filled with water and abrasives is tumbled for polishing. These gemstones are usually roughly shaped and the polishing process is gradual and performed with interval washings. Sometimes, vibratory machines are used in lieu of rotating barrels. This time, the barrels vibrate rather than rotate. Tumbling techniques are also used to polish metal jewelry pieces.

Cabochons Cabbing or cabochon cutting is achieved by gluing or dopping the gemstone into a metal or wooden dopstick or simply holding it in place. The cabbing machine then twirls and creates a round smooth surface top and a flat or slightly rounded bottom for the gemstone. This is usually an alternative to faceting for gemstones that possess too many inclusions.

Faceted Stones Gemstones that have faceted forms reflect brilliant color and clarity from all sides and at all light levels. This technique is most suitable for transparent stones. Today, new techniques like grooves and concave facets are used to create new looks for faceted gemstones.

The Importance of Cut and Polish in Gemstones

Cut is one of the all-important 4C’s and which is used not only to appraise diamonds but gemstones in general as well. Gemstones are often cut with regard to their size alone. But beautifully cut gemstones take their color into consideration as well.

If you are shopping for faceted gemstones, one way of determining the excellence of its cut is to check if its able to reflect light on a consistent level throughout its surface. Look for symmetrical rather than asymmetrical cuts as well. Lastly, be reminded that cut is different from shape.

Polish is simply like adding the final touches to a gemstone. A well-polished gemstone is one with evenly smooth gloss and with no visible scratches on its surface.

There are gem stone mines everywhere around the world. The most popular are in Brazil, Canada, Mexico, Uruguay and Africa. There are also mines in Europe and the United States, depending on what kind of gem stone you are looking for.

Amethyst

Amethyst is the most valuable kind of quartz. It is found everywhere around the world. For this very reason, it is one of the most affordable. The quality of amethyst is quite unique, depending on where it was obtained. Amethyst that are found in the United States are larger compared to those found in Africa. However, the latter has higher saturation when it comes to their colors.

Amethysts with the highest saturation are those found in Australia. There are also amethyst found in Brazil are usually large and have hues and cuts.

Emerald

Emeralds are mostly found in Mexico. Two main sources are the mines in Guerrero and Vera Cruz. Emeralds found there have the tendency to have lighter shades and are clearer than those found in other countries. The stones have lighter hues and the crystals are phantomed with a transparent interior and a saturated exterior.

Emeralds that are found in Guerrero are saturated dark green. They have a visible termination of their interior color saturation and exterior transparency. The highly saturated emeralds are the most elegant.

Sapphire

The most notable source of Sapphires are those found in Brazil from Minas Gerais, Bahia, Maraba and Rio Grande do Sul. Among those containing the best sapphires are the large pockets that are formed by the volcanic material.

The sapphires that are produced here vary in their color saturation which ranging from pale up to medium blue. Those that are navy blue are the sapphires that have the highest saturation.

Diamond

Africa is known to be a producer of diamonds, thus the inspiration of the recently released blood diamond. There are diamond deposits in Zambia and Namibia. The diamonds found in Africa can be as large as an egg and are outstandingly clear.

Jade

The United States has various gems. In Maine, North Carolina, Pennsylvania, Montana and Colorado, the most popular stone is the Jade. The color depends from the medium saturation. It may be smoky or translucent, depending on where it was obtained.

Jade from Maine and North Carolina are usually dark while those found in Montana or Colorado have a green tint.

Now, the next question, how are the jewelry made? Diamonds, emeralds, sapphires, amethysts, and jade are only a handful of precious gemstones out there. Some of them are very valuable because of their rare appearance.

How are these gemstones formed? Well, they are formed underneath the Earth. The process involves vary in each gem stone. The stones react with the minerals, specifically water. This is how they are dissolved. When the solution evaporates and cools down, these minerals are formed.

The water then mixes with the silica-rich rocks like sandstone. This produces the gemstones like amethyst, opals, agates, sapphires, jade and topaz to name a few. When the copper-rich rocks mix with the water, it bears the minerals like turquoise, malachite and azurite.

Emeralds and tourmalines are formed from rain water or the water that is from cooling bodies like magma that is mixed with the minerals and crystallized in cavities or open cracks. These spaces are filled with minerals which create the hydrothermal deposits needed in the formation of these gem stones.

There are also gemstones that are formed directly from the mantle. They consist up to 70% of Earths total mass. They are usually made up of magnesium, silicon, iron, oxygen, silicate and aluminum compounds. The upper layer of the Earths mantle has a volume of the olivine which is quite common in the whole procedure.

Whenever you hear the word metamorphic it means the change of form of these rocks. Metamorphic gems are garnet, emerald, ruby, aquamarine, sapphire, onyx and zircon. They are formed over a long period of time because they wait for the rocks to be altered with such pressure and intense heat in order to interact with the other solutions.

]]> http://knowingjewelry.com/the-gem-stone-mining-and-making-process.html/feed 0