Zincite: Gemstones Information

Zincite is (Zn,Mn2)O and forms translucent, sometimes transparent yellow-orange to deep red hemimorphic pyramidal crystals of the hexagonal system with one direction of perfect cleavage, hardness 4 and SG 5.68. The RI for the ordinary and extraordinary rays is 2.013 and 2.029, uniaxial positive, birefringence 0.016. Zincite occurs as a primary mineral in metamorphosed stratiform zinc ore bodies, virtually the only facetable material coming from Franklin and Sterling Hill, New Jersey, USA.