16.90 Ct. Ethiopian Opal Rough - Height: 28 mm - Width: 15 mm- 3.38 g

Excellent natural Ethiopian rough opal. White base with multicolour fire. Top stone for collectors.
All pictures are taken with a high-resolution camera on dry bone material and on different backgrounds to depict the opal as realistically as possible.
Worldwide shipping with registered mail and tracking number.

An opal is a hydrated form of silica with a water content ranging from 3 to 21%. Indeed, it is this permeability to water that makes it a hydrophile.
Opals are deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. Only precious opals show a variable interplay of internal colors.
At microscopic scales, precious opal is composed of silica spheres approximately 150 to 300 nm in diameter arranged in a hexagonal or cubic close-packed lattice. These ordered silica spheres produce the internal colors by causing interference and diffraction of light passing through the microstructure of the opal.