Section M 5.5.
Home Tour Join! Contents Team News Catalog Search Comm

Phosphates Summary


P2O5 is present in lunar rocks and regoliths at about 0.5wt%. This phosphate is found in the form of Apatite (Ca5(PO4)3(F,Cl)3) and Whitlockite (Ca9(Mg,Fe)(PO4)7(F,Cl)). Both are present as trace minerals, and both exhibit complex substitutions of REEs (Rare Earth Elements). Notable substitutions which occur quite frequently include Y, Nb, Hf, U). REE concentrations in the minerals are higher than those found on Earth.

As would be expected, both minerals are more abundant in KREEPy highland rocks (Highland rocks with high concentrations of potassium, REEs, and phosphor).


Technically, apatite covers minerals of a range of compositions with the following end-members:

Carbonate-apatite Ca5(PO4,CO3,OH)3(F,OH)

Fluor-apatite is the most common, and is a constituent of teeth. It can be synthesized by the fusion of Ca3(PO4)2 with CaF2.

Color depends on the contaminating mineral (e.g., Mn) and the oxidation state of the contaminants (e.g., Mn3+ is blue, Mn7+ is violet). Other colors include green, white, yellow, brown, etc.

Apatite is soluble in HNO3 or HCl.

Apatite is a common accessory mineral on Earth, and is found as an accessory mineral on the moon. Terrestrial apatite may be igneous, metamorphic or sedimentary. Lunar apatites are igneous, and form late during the solidification of the parent melt.


Whitlockite is the most abundant of the two phosphate minerals, and generally has a higher REE content (especially the lighter REEs: La, Ce, and Nd). It can also contain significant FeO, MgO, Na2O, and Y2O3.

Symmetry is trigonal, and it is colorless.


Home Tour Join! Contents Team News Catalog Search Comm
ASI W9700431r1.0. Copyright © 2007 Artemis Society International, for the contributors. All rights reserved.
This web site contains many trade names and copyrighted articles and images. Refer to the copyright page for terms of use.
Author: Richard Marsden. <> Maintained by Richard Marsden <>.
Submit update to this page. Maintained with WebSite Director. Updated Tue, Nov 11, 1997.