Jewelry and Gemstone Glossary of Terms

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Dichroic Glass

A glass which contains ultra-thin layers of aluminum, chromium, silicon, zirconium or the metal alloy titanium. The colors are almost holographic in appearance. Addition of the various elements is what produces the bold and dramatic colors. Colloidal gold may also be added. The appearance will be different depending on whether the light is reflected or transmitted.

More information at Gossamer Glass Studios.

Diffusion

Diffusion is the process of color enhancing a stone by heating the stone in the presence of iron oxide, chrome oxide or similar compounds. The process colors the stone by infusing the outside surface of the stone with color. Only applied to cut stones as any further cutting would remove the color enhancement. This process is often used on sapphires and topaz to heighten or alter the colors.

Dinosaur Bone

Petrified Dinosaur Bone or "dino bone" is the result of fossilized bone from dinosaurs in which the cellular structure has been replaced with quartz, leaving the bone structure intact. It isnow illegal to dig dinosaur bone on government lands so there is less available on the market and the price for quality stone has increased significantly.

Domed

A convex shape like the outside surface of a ball or sphere. This shape is often used in earrings, pendants and components of jewelry designs.

Doublet

A doublet is a layered gemstone with two layers cemented or glued together. This technique is often used with opals to create a gem from a thin vein of precious opal which would otherwise be too fragile to use. The bottom layer is usually an inexpensive mineral such as ironstone or onyx with the opal cemented on top.

Sometimes a layer of clear quartz is added to the top of a thin stone to protect its surface or to enhance its color.

This technique is also used with water clear rutilated quartz where the bottom layer may be black onyx or perhaps blue lapis.

See triplet for a stone with three layers.

Drusy

Drusy (sometimes referred to as: druse, druzy) is a layer of tiny quartz crystals that form on a host stone. The cavity inside a geode is sometimes filled with drusy quartz crystals. Although the quartz crystals may be the source of the color (amethyst, citrine), usually it is the host stone's color (chrysocolla, uvarovite garnet) that shows through the quartz and gives the stone its color. (pronounced: dru-zee)

Dull

The term used to describe gems which exhibit an earthy or dull luster, meaning their surface does not reflect light very well. Plastic can be described as having a dull luster as is clay. Hematite that does not have a highly polished surface will display a dull luster.

dwt.

A measure of Troy weight, dwt. is the abbreviation for "pennyweight", a measure used to weigh gold, silver, and jewels. In Troy weight, the pound = 12 ounces, the ounce = 20 pennyweights, and the pennyweight = 24 grains. While this method of weighing is believed to have originated in Cairo during the crusades, the name comes from Troyes, France where it was first used .

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