set of various dark unpolished minerals with names

background basalt black bornite chromite coal collage collection cutout description flint gabbro gemstone glass gneiss holystone hyalobasalt iron isolated knopite lodestone lujaurite lujavrite magnetite marmatite microgabbro mineral molybdenite name natural nepheline obsidian ore perovskite pumice raw rock rough schorl set shale sphalerite spinel stone syenite tourmaline unpolished various volcanic white