Here is a nice specimen of hyalite opal (opal-AN) on matrix from Zacatecas, Mexico. This piece consists of translucent, colorless, spherical groups of glassy opal with a gemmy appearance. Like most hyalite specimens, this piece shows a brilliant green fluorescence under UV light. A cool piece from this famous Mexican deposit!

Dimensions: 5.4 by 4 by 3.9 cm