"The Mystery of Lyle and Louise"

Dense and massive.

Hematite-cemented quartz; orthoquartzite.

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

Chlorite-bearing.

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

Codeable, 3D-printed robotic hand for interactive STEM learning.

Black, soft; most widely mined.

Slaty cleavage; contains hematite.

Gray to buff, with numerous ooliths and fossil fragments.

Gray, fine-grained, massive contact rock.

Pale pink felsite, with small sanidine phenocrysts.

Used to investigate wavelength in air.

Play sand provides tactile and sensory stimulation necessary for the development of a child's imagination, hand-eye coordination, and fine motor skills such as shoulder stability, forearm rotation, wrist control, and hand strength. Play sand also encourages creativity, visualization and social interaction.

Measure grip strength, pinch strength, and muscle fatigue wirelessly with Go Direct® Hand dynamometer.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

Brownish black, intermediate stage between peat and bituminous coal.