Hyalite Opal Specimen -Mexico

Hyalite Opal on agate matrix 

Hyalite opal is an unusual variety of opal found in various volcanic locations around the world. Because of its unique structure, you won't find any opalescence or "play of color" that traditional opals are known for. Instead, hyalite opal impresses when viewed under both Longwave and Shortwave ultraviolet light, fluorescing a strong green color. Its formation can be classified as amorphous, botryoidal and globular. Its name comes from the Greek word for glass, ýalos (ύαλος), due to its glass-like appearance.

UV photo taken with 365nm Longwave flashlight 

Weight: 47g (with stand)
Locality: San Luis Potosí, Mexico