Description

Opal, also known as hyalite, forms an irregular, globular, purely translucent surface on a gangue of volcanic rock.
The homogeneous internal structure of this type of opal means that no opalescence can be seen.
The piece is large in size.
This piece, from the large collection of Belgian chemist René Hubin, is labelled as coming from Toomwoomba in Queensland, a few hundred kilometers from Brisbane.
According to Mindat, it most likely comes from Dalby, 80 km NW of Toomwoomba.
Video of this Opal (Hyalite) from Queensland, Australia:

This post is also available in: French