Opal Grey

Opal

Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to the amorphous (chemical) physical structure, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt.

Grey

Grey or gray is an intermediate color between black and white. It is a neutral or achromatic color, meaning that it has no chroma. It is the color of a rain or storm cloud, of ash, and of lead.

opal

Noun

1. A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity, of the chemical formula SiO2·nH2O.

grey

Adjective

1. Commonwealth standard spelling of gray.
2. Synonym of coloured (pertaining to the mixed race of black and white).

Verb

1. Commonwealth standard spelling of gray.