Apatite Group Minerals

The apatite group minerals are the most abundant phosphorus-bearing minerals on Earth, typically as accessory minerals in basic to acidic igneous rocks, pegmatites, hydrothermal veins and cavities, carbonates, contact and regionally metamorphosed rocks, and sedimentary rocks (Deer et al. 1996). The principal members of the apatite group include fluoroapa-tite (Ca5(P04)3F), chloroapatite (Ca5(P04)3Cl), hydroxyapatite, and carbonate apatite (Ca5(P04, C03)3(F,0H)) (Deer et al. 1996). 

Chakhmouradian, A.R. and Medici, L. (2006) Clinohydroxylapatite a new apatite-group mineral from northwestern Ontario (Canada), and new data on the extent of Na-S substitution in natural apatite. Ear. J. Mineral, 18 (1), 105-112. 

Compositions of the Apatite-Group Minerals Substitution Mechanisms and Controlling Factors... 

The apatite-group minerals of the general formula, Mio(Z04)6X2 (M = Ca, Sr, Pb, Na..., Z = P, As, Si, V..., and X = F, OH, Cl...), are remarkably tolerant to structural distortion and chemical substitution, and consequently are extremely diverse in composition (e.g., Kreidler and Hummel 1970 McConnell 1973 Roy et al. 1978 Elliott 1994). Of particular interest is that a number of important geological, environmental/paleoenvironmental, and technological applications of the apatite-group minerals are directly linked to their chemical compositions. It is therefore fundamentally important to understand the substitution mechanisms and other intrinsic and external factors that control the compositional variation in apatites. 

This chapter outlines the compositional variations of the apatite-group minerals, with emphasis on the chemical substitutions that appear to be responsible for these variations. We purposely include data from the large number of synthetic apatites, which may or may not... 

A large number of divalent cations (Si, Pb, Ba, Mn, etc.) have been reported to substitute for Ca in the apatite-group minerals. Similarly, many monovalent (e g., Na, ... 

Other ore deposits. The classic fluorapatite specimens and fluorescent specimens are associated with these localities, notably Langban Sweden (ores of Mn, Fe, As), Franklin NJ (Zn), Panasqueria Portugal (Sn, W), and Llallagua, Bolivia (Sn, W). These ore bodies are mainly hydrothermal in origin, but in the case of Franklin multiple alteration events have created unusual species and chemistry. The L igban apatite group minerals are... 

However, the Dy, Sm and Tb emission bands are quite strong (Fig. 18). Contrariwise, Ce emission might be expected to be strong in apatite group minerals with very low concentrations of other REE (and quenching ions), where the individual ions are too far apart on average for efficient energy transfer. 

Apatite group minerals are by far the most prevalent phosphate in sediments. General marine apatites can be hydroxylapatite [Caio(P04)6(OH)2], fluoroa-... 

CHAPTER 18 Apatite group minerals solubility and environmental remediation... 

Apatite Group Minerals Solubility and Environmental Remediation... 

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