Opal-AN (variety hyalite) - Zacatecas (City), Mexico - 45 mm x 21 mm x 17 mm

Mineral: Opal-AN (variety hyalite)
Locality: Zacatecas (City), Municipio Zacatecas, Zacatecas, Mexico
Dimensions: 45 mm x 21 mm x 17 mm

Description: Transparent hyalite in rhyolithic matrix. A colourless variety of opal, hyalite is opal-AN, an amorphous silica-glass containing about 3-10% water.