August 31 – December 9, 2016
Minerals have long been fashioned into gemstones, both as amulets to ward off evil and as adornments. Lapis lazuli was mined in Afghanistan over 6000 years ago, the earliest emerald mines operated in Egypt 3000 years ago, and diamonds were known in India more than 2000 years ago. Today, the nineteenth-century idea that diamond, ruby, sapphire and emerald are the “precious” stones no longer stands. This exhibition of gemstones from the collection of Herb and Monika Obodda illustrates a breadth of color and beauty beyond the familiar four.
A mineral is a naturally occurring solid with an ordered arrangement of atoms and a specific chemical composition. There are approximately 5000 minerals known, of which about 75-100 are used as gemstones, a term generally used for a mineral which is especially attractive, particularly in color. Once cut and polished most gemstones are transparent, but exceptions include lapis, opal and jade. Although some collections of gemstones contain soft minerals, this exhibition focuses on gemstones used in jewelry, prized for their durability as well as their beauty.
One challenge for the admirer or buyer of gemstones is sorting out the various names that have been given by jewelers, online shopping networks and gemstone guides. Diamond is one of the few gemstones known by the same name as the mineral. Other minerals have been given varietal gemstone names, often based on color. One example is the mineral beryl: the green chromium bearing variety is called emerald, the blue green variety is called aquamarine and the yellow variety is called heliodore. Few people realize that the red gem variety of corundum is called ruby and all the other colors of gem corundum are called sapphire.
Gemstones: Aquamarine to Zircon
Curator’s Talk and Reception
Dr. Sharon Fitzgerald, Curator, Mineralogical Museum
Wednesday, October 19, 5-7 p.m.
Mineralogical Museum (Penny Hall)