Whiteite-(CaMgMg)
Whiteite-(CaMgMg) is an IMA-recognized mineral species in the phosphate class, with the chemical formula CaMg₃Al₂(PO₄)₄(OH)₂·8H₂O.
It crystallizes in the monoclinic crystal system (space group P2/a). It is a member of the Jahnsite structural group.
Key properties: Mohs hardness 4; specific gravity 2.48; White streak; Vitreous luster; optically biaxial.
IMA symbol Wt-CaMgMg, IMA status: approved, named in 2016.
A low-temperature secondary mineral presumed to have formed as a result of hydrothermal alteration of phosphate nodules derived from the sediments.
It is found associated with Crandallite, fluorwavellite, montgomeryite, variscite/metavariscite, pyrite, quartz.
The name refers to a member of the whiteite group with the M3 site occupied by Al3+ and the suffix indicates the dominance of Ca at the X site and Mg at both the M1 and M2 sites.