Cobaltite

Cobaltite 

Frequency	common
Hardness	5.5
Density	6.33
Chemical Formula	PbS
Core Elements	Co, As
Thermal Decomposition	PbS 750°C PbO

Character

Pure Cobaltite (CoAsS) would be 165.854g/mol, thus 35.5% by mass cobalt, 45% by mass arsenic, and 20% by mass sulfur.

Roasting

Oxidative roasting below 550°C did not show any crystal structural change in cobaltite but heating to 650°C, yielded Co-As-oxide whose composition varied. Direct oxidation of cobaltite to cobalt oxides with traces of arsenic was observed by roasting at 750°C or above.