Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of the minerals quartz and moganite.
Chalcedony has a waxy luster, and may be semi transparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black.
The name chalcedony comes from the Latin chalcedonius. The name appears first in Pliny the Elder's Naturalis Historia as a term for a translucid kind of Jaspis. The name is probably derived from the town Chalcedon in Asia Minor. A little later the Greek word khalkedon appears in the Book of Revelation (Apc 21,19). It is a Hapax legomenon, a word found nowhere else, so it is impossible to tell whether the precious gem mentioned in the Bible is the same mineral known by this name today.
Chalcedony was a treasured gemstone of the ancient world. No important Roman would be without a seal, amulet or signet ring carved in this fine and durable material. The Victorians, too, prized chalcedony for carved cameos and intaglios: its fine texture allows for delicate and intricate workmanship. Jewelry designers today love its glowing translucent tones and its availability in a wide range of colors and shapes, including carvings.
Durable and easy to care for, chalcedony has a hardness of 7 and enviable toughness even when carved in intricate designs. The seal rings worn by ancient Romans are still in fine shape today.
We use both chalcedony of natural color as well as those with color enhancements.
Here is a photo of silver rind with blue chalcedony and enamel:
Check out more jewelry with chalcedony.