"The Mystery of Lyle and Louise"

Fightly cemented, medium-to-coarse quartz grains.

Pale pink felsite, with small sanidine phenocrysts.

Gray, fine-grained, massive contact rock.

Gray to buff, with numerous ooliths and fossil fragments.

Black, soft; most widely mined.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

Brownish black, intermediate stage between peat and bituminous coal.

Unpolished metamorphic rock with silky lusture, red-brown colour, and clear parallel intergrown quartz crystals.

Lustrous, black 'hard coal'.

Spinel group; black, dull metallic luster; common iron oxide.