Description

Imposing specimen of hyalite opal with a globular, “glazed” appearance, in perfect condition and highly transparent.
The crystallized zone is extensive.
The gangue is basalt.
The chemical formula is that of opal: SiO₂nH₂O.
The word “hyalite” derives from the ancient Greek ὕαλος, “which has the transparency of glass”.
From Toowoomba in Queensland, Australia.
Hyalite opal reacts well to UV light. A specimen from the Hubin collection in Neupré, Belgium and supplied with its label.

This post is also available in: French