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. Size:10x10x5.7 mm. Weight:6.04 ct. CODE#2864