"The Mystery of Lyle and Louise"

Pale pink felsite, with small sanidine phenocrysts.

Light gray, fine small clasts.

Dense and massive.

Hematite-cemented quartz; orthoquartzite.

Pure, large, transparent-to-translucent cleavages, Mohs’ hardness of 4.

Chlorite-bearing.

This spore-forming, thermophilic organism is commonly used for germicidal and sporicidal testing due to its ability to withstand higher-than-normal temperatures.

Gray to buff, with numerous ooliths and fossil fragments.

Gray, fine-grained, massive contact rock.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.