1.3" Poldervaartite Aggregation - N'Chwaning Mine, South Africa

This is an aggregation of poldervaartite on a manganese-rich matrix. The entire specimen measures 1.3" wide and was collected from the N'Chwaning Mine in the Kalahari Manganese Fields of Kuruman, Africa. It's likely that this is an association of Olmiite and Poldervaartite which is common at this mine. Under shortwave UV, the poldervaartite fluoresces a vibrant red-pink color.

Poldervaartite is a calcium and manganese-based mineral, which features Ca as the dominant molecule. This is notable from its chemical formula, (Ca2,Mn)[SiO3(OH)](OH). This is very similar to olmiite, a manganese-dominant mineral with the chemical formula CaMn[SiO3(OH)](OH). Both are found in association with each other in a few known locations in South Africa, most commonly throughout the Kalahari Manganese Fields.

Poldervaartite tends to consist of a peach color enshrouded in a transparent mineral sheath, while olmiite typically exhibits a deeper salmon color, with little to no transparency depending on the specimen's manganese content. Olmiite also displays a deep red fluorescent color when placed under short-wave UV-light, whereas poldervaartite does not fluoresce.
Poldervaartite & Olmiite
N'Chwaning Mine, Kalahari Manganese Fields, Kuruman, South Africa
1.3 x 1.05"