fuckyeahmineralogy: Calcite (CaCO3) crystals covered in specks of pyrrhotite, which can occur in layered igneous intrusions or in pegmatites, along with pyrite, pentlandite, and marcasite.
fuckyeahmineralogy: Calcite (CaCO3) crystals covered in specks of pyrrhotite, which can occur in layered igneous intrusions or in pegmatites, along with pyrite, pentlandite, and marcasite.