HYALITE OPAL SPECIMEN
Hyalite Opal Specimen. This piece fluoresces up under short wave ultraviolet light. This is a superb Aussie specimen to grace your collection. Rare to come by at this quality. Sits on a perspex pad for display.
Squaretop Mountain, Queensland, Australia.
3.2cm x 2.8cm x 2.3cm, 13g.
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.