"WardsSci000478"

Choice yellow-brown, globular to botryoidal crystal groups of this lead arsenate mineral. A secondary mineral in lead deposits forming a series with pyromorphite and vanadinite. Average size: 1" x 1" to 1 1/2" x 1 1/2". Mexico.

Feldspar group; blue-green, microcline, triclinic, ³/₄". Colorado.

Hardened natural cement of calcium carbonate that binds other material such as gravel, sand, clay, and silt.