The density varies, in good part due to the pervasive substitution of arsenic discussed below. Optically, fluorapatite is uniaxial, but the optic sign and indices of refraction vary significantly with As substitution. It is best verified by both X-ray and chemical means. Composition Fluorapatite is a calcium phosphate fluorine mineral of the apatite group. The given analyses indicate much variation in arsenic, which is pervasive in orebody fluorapatite, and show minimal Mn substitution for Ca.
Much work remains to be done on the characterization of local apatites.
Chemical analyses of minerals in the apatite group. The limited given data are slightly misleading in that they do not show completely the variation in Cl, OH, and F in local material. An analysis of apparent johnbaumite was given as one of svabite by Palache, correctly for the time, inasmuch as johnbaumite was not known then and the compositional variation in the apatite group was not understood yet. Svabite is unknown from these deposits. In general, Cl is not present in significant amounts in the high-temperature primary apatites, except for hedyphane and turneaureite.