LARGE HYALITE OPAL
A Large Hyalite Opal. This is a superb Aussie specimen to grace your collection. Rare to come by at this size and quality. Slightly Fluorescent Green under UVC light.
Squaretop Mountain, Queensland, Australia.
16cm x 11.3cm x 3cm, 506g.
Hyalite: SiO2 · nH2O.
A colourless variety of Opal. Hyalite is opal-AN, an amorphous silica glass containing about 3-8% water.
Because it has a different structure, it does not show the opalescence play of colour that is found in precious opal.
Hyalite occurs as globular and botryoidal masses and irregular crusts in volcanic and pegmatite environments where the silica deposits from the gas phase. It often shows a green fluorescence in UV light.