hyalite

Hyalite is another name for this.

Os was already far behind us, and would have been out of sight had not the atmosphere been as clear as hyalite.

Hyalite Canyon, Montana.

Hyalite is a form of opal with a glassy and clear appearance which exhibits an internal play of colors and has natural inclusions.

Tsumebite occurs at Morenci, Arizona, predominantly as twinned crystals associated with wulfenite, olivenite and the hyalite variety of opal.

On the basis of many experiments he succeeded in inventing an original process technology of a black opaque glass called hyalite (1817), as well as completing the production process for red hyalite (1819).