Quartz
Quartz with goldcolored rutile and silverygray ilmenite Scanning electron micrograph of euhedral quartz Scanning electron micrograph of anhedral quartz. These two scanning electron micrographs of doubleterminated quartz crystals ("Herkimer diamonds") come courtesy of Nik Deems. Cryptocrystalline Quartz Minerals. Banded chert from the Fig Tree Formation, South Africa Fossiliferous chert ...