Super thin tabular crystals of Sincosite in groups to maybe 0.5mm. It is associated yellow Hawleyite. The matrix is the black Phosphoria Formation. This area of the country boast large reserves of phosphate deposits with several producing mines. The formation is so black early pioneers assumed it was coal. But it they couldn't burn it!
Sincosite
Formula
Ca(V4+O)2(PO4)2·5H2O
Crystal System
Tetragonal
Crystal Habit
Scaly, Platy, Aggregates
Cleavage
Perfect, Distinct, Poor
Luster
Vitreous - Metallic
Color
green, yellowish green, olive green, brownish green