Formula: CaMn²⁺[SiO₃(OH)](OH)

Species:

Colour: Pale to intense reddish pink.

Lustre: Vitreous

Hardness: 5 – 5½

Specific Gravity: 3.05

Crystal System: Orthorhombic

Name: Named for Filippo Olmi (1959-2005) who worked at CNR, Centre di Studio per la Minerogenesi ela Geochimica Applicata, Florence, Italy.

Type Locality: N’Chwaning II Mine, N’Chwaning Mines, Kuruman, Kalahari manganese field, Northern Cape – South Africa

Mn²⁺-dominant analogue of Poldervaartite. A product of hydrothermal alteration.