Whether it’s understanding gemological or jewelry terms in an article you’re reading or simply gaining a greater understanding of the world of jewelry and gemstones, our Jewelry & Gem Dictionary is a handy reference guide. And, unlike most dictionaries, ours makes for interesting reading all on its own!

Ebonite (also called vulcanite) is a hard, moldable, polished dark colored (ranging from brown to black) early rubber. Ebonite was produced by adding sulfur to vulcanized rubber. It was used for combs, ornaments, and buttons. Ebonite is sometimes confused with gutta percha.

Ebony is a hard, dark, dense wood sometimes used in jewelry. Wood has recently become a very popular material in contemporary jewelry.

The Edwardian period (also known as the Belle Epoque) was the time of the reign of Edward VII of England (1901-1910). Edwardian jewelry is delicate and elegant. Edwardian designs frequently use bows and filagrees. Pearls and diamonds were also frequently used.

Eilat stone is only found in King Solomon’s copper mines on the Red Sea, near Eilat, Israel. This opaque green mineral is composed of azurite, malachite, turquoise, and chrysocolla. The hardness of this copper-based stone varies. There are many variations on its spelling, including Eliat, Elat, and Ellat.

Electroplating (also called Galvanotechnics after its inventor, Luigi Galvani) is a process in which one metal is coated with another metal using electricity. In jewelry, inexpensive metals are frequently electroplated with more expensive metals, like gold (gold plating), copper (electrocoppering), rhodium (rhodanizing), chromium (chromium plating), or silver (silver plating). The thickness of the metal coat varies. Electrogilded coating is the thinnest (less than 0.000007 inches thick); gold-cased metals have a coating thicker that 0.000007 inches.

Electrum is an amber-colored alloy of gold and silver that was used in ancient times. Electrum is also an alloy used in medieval times consisting of copper (50%), nickel (30%) and zinc (20%).

An Elie ruby is actually a pyrope garnet (and not a ruby at all).

Embossing is a method of surface decoration in which a design is raised slightly above the surface. Sheets of metal, leather, and plastic can be embossed.

Emeralds are a very hard, green precious stone (beryl, Be3Al2Si6O18, colored by chromium and some vanadium impurities). Flaws and cloudiness (called jardin) are very common in emeralds, so many emeralds are oiled, irradiatied,and dyed to improve their look. Synthetic emeralds (developed by Carroll Chatham in the 1930’s) have fewer imperfections and are very hard to distinguish from natural emeralds. Emeralds belong the beryl group of stones which also includes aquamarines, morganite, and chrysoberyl). Emeralds have a hardness of 7-8 and a specific gravity of 2.6 – 2.8. Emerald (and all forms of beryl) have large, perfect, six-sided crystals. Emeralds were long thought to have healing powers, especially for eyesight. During the renaissance, emeralds were used as a test for friendship among the aristocracy; an emerald given to a friend would remain perfect as long as the friendship endured.

Emerald cut stones have a girdle that is rectangular with truncated corners. Emerald cuts are frequently used on emeralds and diamonds.

Enamel is a glassy substance (powdered glass with colorants) fused onto metal using heat

Engraving is a method of surface decoration in which a design is etched into the surface with a sharp tool.

Treatments, such a heating and oiling, that are an accepted part of the process of gemstone cutting and polishing. The AGTA only approves of enhancements that are permanent, do not counterfeit the beauty of the gem, and only tap the natural potential beauty of the gem.

An etched finish on a metal’s surface reduces the metal’s reflectivity. It is done by using harsh chemicals to eat into the surface or by cutting into the surface using a sharp tool.

An eternity ring is a narrow ring with a ring of gemstones.

Ancient Etruscan jewelry has intricate and beautiful designs; most is made of gold. The Etruscans employed a lot of delicate granulation (n which tiny beads of gold are soldered to the surface to form a pattern) and openwork filagree (in which filagree patterns are not applied over sheet metal). The Etruscans lived in Northern Italy for hundreds of years beginning in the late 8th century B.C.

The style of diamond cutting popular from approximately 1890 to the 1930’s. Unlike the old mine cut preceding it, the European cut has a round girdle (perimeter) made possible by the introduction of the power bruting machine (bruting is the term for shaping the girdle of a diamond, the first step in the cutting process). The European cut can be distinguished by the size of the table (the top, flat facet) in relation to the diameter of the stone. In a European cut, the table is smaller in relation to the diameter of the stone. Also, the culet (the bottom facet) is often large, appearing to create a hole at the bottom of the diamond, when viewed from the top, since the large culet lets light escape instead of reflecting it back to the viewer.

A gemstone with no inclusions visible to the unaided eye.

An eyepin is a thin wire with a loop at one end; it is used for linking beads together.

The Excelsior is the second- or third largest diamond (depending on whether or not the Braganza diamond was actually a diamond). This irregular-shaped blue-white diamond was roughly 995 carats. It was found in l893 by a worker at the De Beers mine at Jagersfontein, Orange Free State, South Africa. The Excelsior diamond was cut in 1904 by I.J. Asscher and Company of Amsterdam into 21 stones, including a 69.80-carat marquise, an 18-carat marquise stone (which was displayed at the l939 World’s Fair by the De Beers company), and many other stones.

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