磷灰石

Apatite — the calcium phosphate group, dominated by fluorapatite — is the most abundant phosphate mineral and a popular collector species for its range of colours and sharp hexagonal prisms. Its name comes from the Greek apatáo (“to deceive”), for how readily it is mistaken for other minerals such as beryl or tourmaline.

Forms and colours

Gem apatite occurs in vivid blue, green, yellow, purple, and pink, often as transparent hexagonal prisms, and is a common accessory in granites, pegmatites, and skarns worldwide. It is a frequent associate on specimens of other species, perched on quartz, mica, or feldspar.

The Chinese angle

In China, apatite turns up across the Nanling W-Sn deposits and the rare-earth and skarn systems. At the Bayan Obo deposit fluorapatite is a major rare-earth-bearing phase, and crystallised apatite accompanies fluorite and cassiterite at localities in Hunan and Sichuan.

Collecting notes

Apatite is moderately soft (Mohs 5) and can be brittle, so undamaged terminations and saturated colour drive value. Gemmy, well-terminated single crystals and aesthetic associations on matrix are the most sought-after.