This sample exhibits a combination of three minerals each in their separate crystal phase. The lengthy white crystals are of Quartz, in nature an abundant mineral, chemical formula SiO2. The bluish-grey crystals in between are of Galena, a lead sulfide (PbS) The substrate with its gold-like luster is Chalcopyrite, a copper iron sulfide (CuFeS2). This is a rare combination for a natural rock. That such very different minerals are combined in one sample is only possible on account of each having been deposited in completely separate phases of mineral deposition. Sample is from Bulgaria, actual width is 210 mm.