Fire Agate

Item Description

Agate is a form of chalcedony or microcrystalline quartz that forms in layers in a remarkable variety of colors and textures. The most familiar Agate is the banded agate which has multicolored layers. Idar-Oberstein, Germany was once famous for its Agate mines, and agate carving there has a long tradition that continues to this day. Agate has an even longer history beyond Europe since the Egyptians used it as a gemstone more than 3,000 years ago. But one of the rarest forms of Agate - Fire Agate - has been available commercially only in the last 60 years. Fire Agate is a brown Agate that has a botryoidal or grape-like growth form. What is special about fire agate is that it contains layers of plate-like crystals of iron oxide (limonite) in various planes. The iridescent colors of red, gold, green, and, occasionally, blue-violet, result from interference between diffracted light rays traveling through and reflecting from these thin layers. High-quality Fire Agates can be as impressive in their play of color as fine Black Opal, but Fire Agate is significantly more durable than Opal. Fire Agate is suitable for any kind of jewelry, including rings. This "Freeform Cabochon" is a beautiful example of this well-known material, showing bright green, gold, and orange flashes when rotated in the light, which dance over the botryoidal forms. Donated to the Rice Museum by a local donor, for this benefit auction.