Chemical composition of manganese deposits (Birnessite) from Scotland

A manganese pan near Birness contains grains of an optically uniaxial negative mineral near (Na0.7Ca0.3)Mn7O14·2·8H2O, giving an X-ray powder pattern similar to that of synthetic materials described as 'manganous manganite' and delta-MnO2. Material giving a similar pattern has been described from a natural occurrence in Canada, but no mineral name was assigned; the name birnessite is now proposed. The mineral is probably formed by air-oxidation of manganous oxides under alkaline conditions.伯内斯（Birness）附近的锰质盘中产出了成分接近(Na0.7Ca0.3)Mn7O14·2.8H2O的光性负一轴晶矿物晶粒，其X射线粉末衍射图谱与被称为“亚锰酸锰矿（manganous manganite）”及δ-二氧化锰（delta-MnO2）的合成材料的衍射图谱相似。此前已有研究在加拿大的天然产出物中发现了具有相似衍射图谱的物质，但未为其赋予正式矿物名称；现提议将该矿物命名为水钠锰矿（birnessite）。该矿物大概率是在碱性条件下经空气氧化亚锰氧化物形成的。