GLOSSARY OF TERMS

     cabochon-Cabochon is a term used to indicate a smooth round or oval convex shaped highly polished, unfaceted gemstone.

     dichroic glass-Dichroic is defined as the property of having more than one color. Dichroic glass appears to be different colors when viewed from different angles or with different amounts of light. Dichroic glass is produced by adding thin layers of metallic oxides upon the surface of the glass in a high temperature, vacuum furnace. The metalic oxide layers transmit some wavelengths of light while reflecting others. Thus an iridescent effect is produced in the resulting dichroic glass.

     gemstone-A gemstone is a crystalline precious or semi-precious stone, a mineral, rock, or petrified material that when cut or faceted and polished is used in jewelry or is collectible.
     natural gemstone-Natural gemstones include minerals and organic materials such as emeralds, rubies, sapphires, amber, coral, fossil, ivory, cultured freshwater pearls and natural saltwater pearls that occur in nature with no alterations from humans.
     sim. (simulant) gemstone-Simulants gemstones are laboratory grown and have an appearance similar to that of a natural gemstone. They have, however, different optical, physical, and chemical properties.
     syn. (synthetic) gemstone-Synthetic gemstones are laboratory grown and have essentially the same appearance and optical, physical, and chemical properties as the natural material that they represent.

     karat (abbreviated k or kt)-Karat is a unit of measure for the fineness of gold, equal to 1/24 part. Pure gold is 24 karat so gold that is 50 percent pure is 12 karat.

     mm-The millimeter (abbeviation mm) is a metric system unit of measurement. It is used to measure length. It is 0.001 (1/1000th) of a meter or 0.1 (1/10th) of a centimeter. (It takes about 25.4 mm to equal 1 inch.) To see how to use a metric ruler click on the “Using a Metric Ruler” button on the left side of this page.

     oco geode (Brazil)-A geode is a rock containing a cavity usually lined with crystals or other mineral matter. Oco is Portuguese for hollow or concave. The geodes that form in Brazil usually have quartz interiors. One theory about how geodes form is that they form from the outside in with silica dissolved in water slowly seeping into an opening in the geode. The center remains hollow if the entrance is blocked before it fills up. If it continues to fill up then the center becomes solid. A second theory about how geodes form is that a liquid siliceous ball was deposited at the same time as the host rock and then the liquid becomes solid over time. Other theories have been given as to how they form. In any case, it is not known how long it takes for geodes to form but is believed to be about 240 million years. The geode slices used in the geode pendants were carefully sawed and then ground and polished.