is Copper Arsenicum Sulfide with formula Cu3AsS4 and hardness of 3.5.
I had this material many years ago from a mining prospector who performed some researches in the Luzon island, Philippiness; type locality for this material.
Is often mixed with other mineral such enargite and famatinite.
Metallic luster,heavy with small niches on surface. A odd stone for a systematic collection.
Weight: 4.1 ct.