POLDERVAARTITE now OLMIITE (miniature)

Poldervaartite, renamed OLMIITE,  is an exceptionally rare mineral first identified in 1992 at the Wessels Mine located in the Kalahari manganese fields of Northern Cape Province, South Africa. Its chemical composition is represented by the formula (CaMn2+)2(SiO3OH)(OH), classifying it as a Calcium Manganese Silicate Hydroxide, with a molecular weight of 197.68 grams. To date, the Wessels Mine and the nearby N’Chwaning Mine remain the sole known sources of this mineral. Poldervaartite exhibits a specific gravity of 2.91 g/cm³ and a refractive index ranging from 1.634 to 1.656, categorized as Biaxial (+). Due to the majority of its crystals being unsuitable for faceting, it is considered a very rare gem, displaying colors that vary from colorless to a light orangish-pink.