The Language of Gemstones and Jewelry
Jewelers and gemologists will speak about jewelry and gemstones in a very specific way using a particular language of terms. The more knowledge you have in approaching any purchase, the more prepared you’ll be to know exactly what is being discussed and what that means for the gem or piece of jewelry you are considering. To help with that, we’ve put together the most helpful information on this page so that every conversation and consideration will be totally clear.
Gemstone Cutting Terminology
In antiquity, if rubies were worked at all, they were fashioned into cabochons . Cabochons are the simplest cutting style featuring a curved upper surface and a flat or slightly curved underbelly. The upper part of a cabochon may be a simple dome or a series of curved surfaces that meet in a pyramidal arrangement – this is known as a sugarloaf cabochon.
A cabochon may be any shape, but circles and ovals are most often the ones you’ll see. It costs less to create a cabochon than a faceted stone, and the quality of the rough is less critical. Beautiful cabochons can be made from lower quality crystal material that is considered unsuitable for turning into a faceted gemstone.
With the advent of improved gem cutting technologies, lapidaries were suddenly able to cut facets into gemstones. Facets are the flat, polished surfaces of a finished gemstone. In the earliest days of gem cutting, many stones were first given a table cut, which created a single polished face on the top of the stone.
Later, rose cuts became popular and have been gaining in popularity again in recent years. A rose cut stone will typically have a flat bottom and radiating triangular facets that come to a point at the top of the stone. Continuing to develop varied cutting techniques, lapidaries today focus on using three key cutting styles to create faceted stones: brilliant cuts, step cuts, and mixed cuts.
While brilliant cuts employ radiating facets emerging from the center of the stone, step cuts consist of parallel facets. A majority of emeralds are cut in a variation of the rectangular step cut, called an “emerald cut” for the gemstone it was created for to enhance its best features. For rubies, the facets of a brilliant cut create a lively expanse of color.
Alternately, the parallel arrangement of step-cut facets allows cutters to adjust the finished stone’s proportions to the shape of the rough crystal as they go. Step cut rubies may not have the same sparkle as those with brilliant cuts, but in exchange they offer broad, uninterrupted expanses of color.
The mixed cut combines a brilliant cut crown with a step cut pavilion. Mixed cuts are a fairly modern cutting style that offer significant advantages over brilliant cuts and step cuts. The crown of mixed cuts is brilliant cut to maximize the brilliance and sparkle of the stone and to help obscure minor clarity issues. The pavilion is then step cut to save weight and help enhance the color of the stone.
Briolettes are stones cut in a rounded fashion to make a faceted teardrop shape. This particular cut looks especially appealing dangling from an earring or pendant.
Additional information for evaluating cut is provided in the discussion of Tips for Buying Ruby Jewelry.
Mountings and Settings
The basics of gemstone mountings and settings help form a useful foundation to mix your tastes with practical choices for a stone. The mount refers to the entire precious metal item before any stones are set in it. Mounts may be rings, necklaces, pendants, earrings, bracelets, brooches and cufflinks. Gemstones are incorporated into mounts with a variety of popular setting styles including the following:
Bezel setting: a strip of metal will encircle the edge of the stone to create the setting. It is also called a rub-over setting. This is a popular means of setting cabochons.
Prong setting: also called a claw setting, this popular style has pointed, rounded, flat, or v-shaped metal supports called prongs or claws that are used to hold a stone. Typically, a combination of four or six prongs is used, but more or fewer may be used to create a desired effect.
Flush setting: this setting does not use prongs or a bezel. For this style, gems are set directly into the jewelry so that the top of the gem is flush with the metal surrounding it.
Pavé setting: a popular setting style where the stones are placed close together to hide seeing the metal mount. The name comes from the fact that the finished piece looks like it has been paved with stones.
Channel setting: in this style, stones are set into a grooved channel with no metal separating them from beneath. A bar setting is similar, but stones are held in place by parallel bars on either side.
Invisible setting: a very difficult setting to execute, in this one stones are grooved just below their girdle and slid over wire supports. This allows many gems to be placed together with no gaps between them giving the effect that they are not in a setting at all. This setting was invented by the famous design house Van Cleef and Arpels.
Tension setting: a modern setting that requires no bezel or prongs where the stone seems to float in mid-air with no support from underneath. In this setting, a gemstone is held in place by the precious metal shank or band, which presses on the stone’s girdle in a spring-like manner to keep it secure.
Precious metals are made into pieces of jewelry by employing four common methods: die striking, wax casting, electroforming, and hand fabrication. These techniques are not mutually exclusive and in fact are commonly use together for finished jewelry.
Die striking or stamping is a very old technique for creating jewelry. It can be a rapid and cost effective means for producing large quantities of goods. The stamping process also produces dense and durable goods that wear well and take a high polish.
Because it produces items that are naturally strong, the die striking process is especially recommended for the manufacture of prong settings, although it is also commonly used to make pendants and earrings. The process begins with the creation of a die, which is usually comprised of two parts–a punch and a mold. The dies are mounted into powerful machines that are fed blanks of precious metal. When the blanks are struck by the die, a three dimensional piece of jewelry is created.
Modern wax casting methods are actually derived from an ancient Egyptian technique for shaping materials. Although the results are not as dense as die struck pieces, the casting technique is a relatively quick and efficient means of making many identical jewelry pieces. Today, the process involves first making a wax model in a rubber mold. Identical wax models are then attached to a wax “tree” and covered with a plaster-like material, called investment. Once the investment has dried, it is heated and melted wax is drained from the mold. The empty space left behind is filled with molten metal and allowed to solidify. When the investment is removed, the result is a precious metal “tree” of castings. The castings are then clipped from the trees, cleaned, and polished.
Electroforming is a technique that uses electricity to place metal over a model. Electroformed jewelry is not as durable and more difficult to repair than jewelry produced by other means, but the products are quite lightweight and are capable of having intricate detailing. In this technique, a wax model is attached to a frame and submerged in a unique chemical bath. An electrical current gives the models a positive charge, attracting negatively charged particles of precious metal. When the metal layer is thick enough, the wax model is melted away, and a hollow piece of precious metal jewelry is created.
Our final technique is uncommon to find in modern jewelry: one-of-a-kind hand fabricated jewelry pieces. When a jewelry item is hand fabricated, that means it is made entirely with hand tools and methods including sawing, carving, hammering, and soldering. These techniques can be very time consuming and require a great level of skill. Because there is some ambiguity over the term “hand made,” jewelers generally prefer to use the more precise term “hand fabricated.”
Using A Jeweler’s Loupe
A 10x lens or jeweler’s loupe is one of the most valued of all instruments for gemological observation and identification. Not only is the loupe easily transportable and inexpensive it’s useful for identifying items of any size, transparency, or condition. It’s invaluable for examining both the surface features and interior of all manner of crystal rough and faceted gemstones.
When using the loupe, the primary goal is to position and maintain the eye, the lens, and the object at a fixed distance from one another. This is done by first resting the hand holding the loupe on the cheek and then positioning the loupe about one inch from your eye. The gemstone or object being examined should be held in the other hand (often in tweezers or a stone holder). To steady yourself, keep both hands in contact with each other as the object is viewed. You may also lean onto a table or lock your elbows to steady yourself.
You’ll want to keep both eyes open when viewing an object. If you wear glasses, they can be left on, and just remember to relax and breathe normally. Turn the stone to view it from different angles without losing focus—keeping the distance from the eye, the lens, and the objects fixed.
Lighting is important. Stones should be lit from the side or the back and examined against a non-reflective background. You should avoid direct sunlight when using a loupe, but daylight is good for examining stones. Table lamps and penlights are also recommended as illumination sources. If you use a table lamp or penlight, hold the stone under the light, but keep the loupe itself out of the light.
Now that we’ve covered this additional terminology, next explore our Glossary for a comprehensive look at concepts and definitions you need to know.