Creamy yellow crystals of Calcite have been completely replaced by Dolomite on Quartz and Galena. A classic specimen from the South Tamar Mine, Bere Alston, Devon. The replaced Calcite crystals measure to 3cm with a platy rosette lenticular habit. Formed on ridges of Quartz crystals with intergrown crystals of metallic lead grey Galena. The specimen comes with a white R.W.Barstow label, and a partial label stating it was an exchange with the Geological Survey in 1980. This old mine is believed to have been at work in the late 13th century for the relatively high silver content of the ore.