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Dense and massive.

Hematite-cemented quartz; orthoquartzite.

Fine, common limestone; massive, and will fizzle with HCl.

Black, soft; most widely mined.

Light gray, earthy.

Soil

Red-brown to gray, coarse-grained, containing feldspar and mica.

Light gray, fine small clasts.

Compact Plant Fiber Masses.

Useful for weathering and erosion, soil formation, porosity and permeability, or other general earth science labs.

Buff, coarse, crystalline “Austin Marble” with shell casts and molds.

Black, fissile; commonly with carbonized fossil plant impressions.

Red, medium, to coarse-grained iron oxide cement; shows hematite bands.

Gray, fine to medium-grained “Berea grit”.

Brownish gray, kerogen-rich; commercial oil source.

1 pound of black sand packaged in a heat-sealed bag.