CHRYSOCOLLA
Chrysocolla has a nice, deep, rich turquoise-like
color. In the past, it has been called turquoise. It’s usually
amorphous, and only partially forms crystals at best. It is a hydrous
copper aluminum hydrogen hydroxy-silicate mineral ((Cu,Al)2H2Si2O5(OH)4·nH2O).
It typically forms as a secondary mineral in copper-bearing rocks.
Chrysocolla is greenish to bluish, is soft to
moderately soft (H = 2 to 4), with an earthy to vitreous luster, no crystal
form, and no cleavage.
Chrysocolla (blue) (2.3 cm across), mixed with tenorite (black) from northern
Michigan's Algomah Mine. At Algomah, tenorite and chrysocolla are the
main copper ore minerals.
Chrysocolla (5.5 cm across) from Shaba/Katanga Province, Zaire ("D.R.
Congo").