This is a Manganoan Calcite from, N’chwaning Mine lll, Kalahari Manganese Field, Northern Cape, South Africa
Crystal Dimensions: 12.5cm (4.9”) x 8cm (3.1”)
Crystal Weight: 392 grams
Manganoan calcite or manganocalcite is a variety of calcite rich in manganese, which gives the mineral a pink color.
Its chemical formula is (Ca,Mn)CO 3.