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1.8" Lustrous Olmiite on Calcite - N'Chwaning Mine, South Africa
This is an association of lustrous olmiite crystals that formed over calcite crystals. The entire specimen measures 1.8" wide and was collected from the N'Chwaning Mine in the Kalahari Manganese Fields of Kuruman, Africa. Under shortwave UV illumination, these crystals fluoresce a red-pink color.
Olmiite is a calcium and manganese based mineral with the chemical formula CaMn[SiO3(OH)](OH). Olmiite crystals typically exhibit a salmon color, with little to no transparency depending on the specimens' manganese content. It is often found in association with poldervaartite in a few known locations in South Africa, most commonly throughout the Kalahari Manganese Fields. Like poldervaartite, olmiite commonly displays a dull-red fluorescence when placed under shortwave UV-light.
About Calcite Crystals
Calcite crystals are a form of calcium carbonate (CaCO₃) known for their diverse shapes, transparency, and vibrant range of colors. They typically form in rhombohedral, scalenohedral, or prismatic shapes, often with well-defined, sharp edges and glossy surfaces. Calcite crystals are often translucent or transparent, sometimes displaying a double refraction effect where objects viewed through the crystal appear doubled. They can appear in various colors—white, clear, yellow, pink, blue, green, and orange—depending on impurities or trace minerals.
A notable characteristic of calcite is its reaction with weak acids like vinegar, which causes it to effervesce, or fizz, as it releases carbon dioxide. This property makes calcite crystals a key tool in geological identification and studies. Calcite forms in many environments, from sedimentary rocks like limestone and marble to hydrothermal veins.
Calcite crystals are a form of calcium carbonate (CaCO₃) known for their diverse shapes, transparency, and vibrant range of colors. They typically form in rhombohedral, scalenohedral, or prismatic shapes, often with well-defined, sharp edges and glossy surfaces. Calcite crystals are often translucent or transparent, sometimes displaying a double refraction effect where objects viewed through the crystal appear doubled. They can appear in various colors—white, clear, yellow, pink, blue, green, and orange—depending on impurities or trace minerals.
A notable characteristic of calcite is its reaction with weak acids like vinegar, which causes it to effervesce, or fizz, as it releases carbon dioxide. This property makes calcite crystals a key tool in geological identification and studies. Calcite forms in many environments, from sedimentary rocks like limestone and marble to hydrothermal veins.
SPECIES
Olmiite & Calcite
LOCATION
N'Chwaning Mine, Kalahari Manganese Fields, Kuruman, South Africa
SIZE
1.8 x 1.7"
CATEGORY
ITEM
#169766
