Your Guide to Precious Gems and Jewelry Learning the Lingo What About Carats Evaluating Color Judging Transparency and Clarity All About Cuts Learn About Cat’s Eye and Stars Pros and Cons of Synthetics What Are the Different Types of Stones Evaluating Gemstones How to Spot Fraud Caring for Your Jewelry Where and How Gemstones Are Mined Buying Wholesale Hand-crafted Jewelry
Learning the Lingo
Jewelry with a Capital J, Understanding Basic Jewelry Terms, Processes, and Techniques
It is easy to feel intimidated and out-of-place when you’re visiting a high-class jewelry store for the first time. To avoid making unwanted and uninformed purchases, improve your knowledge about jewelry starting with the tips below. If you speak the same language people in the jewelry industry speak then you’ll go home with the jewelry piece you want, need, and definitely can afford.
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. It may even be harvested like pearls or organic material 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 changed and expanded 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 uses finer abrasives. 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 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 way, 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 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 it’s 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 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.