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Help needed on the following points. In 1815 was the most common manganese ore referred to as pyrolusite? Was it referred to as black oxide at any time? In 1815 was Upton Pyne the main UK source and when did this mine cease production of pyrolusite? Does anyone know the very approximate content of manganese dioxide in the ore from Upton Pyne? Thanks in anticipation. Fred. Kington, Herefordshire