Covellite

Covellite
Picture needed
General
Category	Mineral
Chemical formula	copper(II) sulfide:CuS
Identification
Color	Indigo blue (tarnished to purple or black)
Crystal habit	thin platy hexagonal crystals also massive to granular.
Crystal system	Hexagonal 6/m2/m2/m
Cleavage	Perfect in one direction
Fracture	flakey
Mohs Scale hardness	1.5 - 2
Luster	metallic
Refractive index	opaque
Pleochroism	N/A
Streak	lead gray to black
Specific gravity	4.6 - 4.8
Fusibility	2.5
Solubility	?
Other Characteristics	micaceous cleavage
Major varieties

Covellite (also know as covelline) is a crystalline form of copper(II) sulfide (CuS). In appearance it is an enchanting indigo blue. It is associated with chalcosite in zones of secondary enrichment (supergene) of copper sulfide deposits. Commonly found with and as coatings on chalcocite, chalcopyrite, bornite, enargite , pyrite, and other sulfides. Often occurs as pseudomorphic replacements after other minerals. Very rare occurrence as a volcanic sublimate at Mount Vesuvius the site of its discovery or first description by N. Covelli (1790 - 1829).

References and external links

• Dana's Manual of Mineralogy ISBN 0471032883
• Mineralgalleries.com
• Webmineral
• Mindat.org