"Freeze-Dried Specimens"

Dark gray with abundant gas pocket vesicles.

Volcanic glass with snowflakes embedded throughout.

Black, soft; most widely mined.

Pale pink felsite, with small sanidine phenocrysts.

Lustrous, black 'hard coal'.

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

Silvery, paragranite and muscovite-rich with medium garnet crystals.

Samples of Intrusive and Extrusive Igneous Rocks

White and black bands of quartz, feldspar, and biotite; typical foliation.

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