Highlights in Applied Mineralogy by Soraya Heuss-Aßbichler Georg Amthauer Melanie John

Author:Soraya Heuss-Aßbichler,Georg Amthauer,Melanie John
Language: eng
Format: epub
Publisher: De Gruyter
Published: 2018-06-01T04:00:00+00:00

9.4.2Apatite type

As one of the most abundant phosphate minerals, apatite can be described as M10(TO4)6X2. The two crystallographically distinct M-sites are usually occupied by Ca2+ but can accommodate REE as well. T represents P and/or Si, while X can be F, OH, Cl, or O. The mineral name is derived from the Greek word for “misleading” or “deceive” (απατείν) because different varieties of apatite were regularly mistaken for other minerals.

It is common in placers and as an accessory mineral in igneous rocks [27–29]. U-bearing apatite from the Oklo natural reactor in Gabon was found to be 2 billion years old, indicating a high long-term stability [30, 31].

A detailed study of the structure of apatite was presented by Hughes and Rakocvan [27]. Having the hexagonal space group P63/m, the approximate lattice parameters of apatite are around a = 9.4 Å and c = 6.8 Å. The occupied Wyckoff positions are given in Tab. 9.2.

Tab. 9.2: Occupied Wyckoff positions in the apatite-type structure in space group P63/m.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.