Phosphate Minerals as Gemstones

Although some remarkably striking gemstones can be cut from phosphate minerals (Chapter 2), these minerals have usually been listed as less well known or as collector s items . In some cases, limitations as gemstones arise from fragility or insufficient hardness. The best known of these gan-stone phosphates is turquoise (Table 5.23). 

A recent classification [75a] lists some 20 different (ortho)phosphate minerals as gemstones. They include turquoise, beryUonite, brazilianite and lazulite with Moh s hardness stated to lie in the range 5.5-6.0. 

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