ABSTRACT

The mineral unknown A reported by Bridge from the Petrogale Cave in Western Australia has been shown to be phoxite, a recently described mineral from the Rowley mine in Arizona, USA. This is only the second recorded occurrence of phoxite, and while at the type locality, it occurs with struvite, (NH₄)Mg(PO₄)·6H₂O, at the Petrogale Cave, it occurs with weddellite, Ca(C₂O₄)·2H₂O. Phoxite can be synthesised from struvite or newberyite, MgHPO₄·3H₂O, by reaction with ammonium oxalate in water or by grinding the solids together. Mixing newberyite or struvite with ammonium oxalate in high humidity enables a clean synthesis of phoxite. A competing reaction is the formation of magnesium oxalate dihydrate (the mineral glushinskite). However, while stable in the solid, washing with water allows phoxite to revert to struvite, as part of a solid liquid equilibrium.

摘要

Bridge 报道的来自西澳大利亚 Petrogale 洞穴的未知矿物A已被证明是磷铁矿，这是一种最近描述的来自美国亚利桑那州 Rowley 矿的矿物。这仅是第二次有记录的磷铁矿，而在模式产地，它与鸟粪石（NH ₄）Mg(PO ₄ )·6H ₂ O 一起出现，在Petrogale Cave，它与威德石Ca(C ₂ ) 一起出现O ₄ )·2H ₂ O. 磷灰石可由鸟粪石或新镁橄榄石合成，MgHPO ₄ ·3H ₂O，通过与水中的草酸铵反应或将固体一起研磨。在高湿度下将新镁橄榄石或鸟粪石与草酸铵混合可以清洁合成方磷铁矿。一个竞争反应是草酸镁二水合物（矿物 glushinskite）的形成。然而，虽然在固体中是稳定的，但用水洗涤可使磷灰石恢复为鸟粪石，这是固液平衡的一部分。