Hydroxyledgrewite
Hydroxyledgrewite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₉(SiO₄)₄(OH)₂.
It crystallizes in the monoclinic crystal system (space group P2_1/b). It is a member of the Humite structural group.
Key properties: Mohs hardness 5.5; specific gravity 2.916; White streak; Vitreous luster; optically biaxial.
IMA symbol Hegr, IMA status: approved, named in 2011.
Found in xenoliths of carbonate-silicate rock altered to sanidinite facies metamorphic rock within ignimbrites.
It is found associated with Bultfonteinite, hillebrandite, jennite, chegemite, larnite, rondorfite, hydroxylellestadite.
The name refers to its relation to edgrewite and dominance of hydroxyl over fluorine.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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