Opal is silica, just like quartz, agate, jasper and other silica minerals.  However, opal does not have a crystaline structure, but is made up of tiny amorphous balls – lined up and organized to various degrees.  Fire Opal shows beautiful flashes of reds, blues, greens, yellow – due to the amorphous balls lined up in layers – providing optical properties to exhibit strong colors.  Some opals are not well organized into layers and hence, show little color.  Our brownish beads are a mix of rhyolite igneous rock with bits of opal distributed throughout – groundwater has percolated through the rock, redistributing the silica to form pockets and streaks of opal.

Opal Butte
Morrow County
Oregon, United States

Opal Butte produces a variety of opals within the Cenozoic Columbia River Basalts. The white opal in these beads formed in interspersed rhyolite beds – the brown material of these beads.

Opal Butte, Morrow County, Oregon

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