Ercitite
Ercitite is an IMA-recognized mineral species in the phosphate class, with the chemical formula NaMn³⁺(PO₄)(OH)·2H₂O.
It crystallizes in the orthorhombic crystal system (space group Cmca).
Key properties: Mohs hardness 3–4; specific gravity 2.77; Beige streak; Vitreous. Streak: Beige luster; optically biaxial.
IMA symbol Erc, IMA status: approved, named in 1999.
Found in a zoned, rare-element granitic pegmatite, as an overgrowth on collinsite-fairfieldite, whitlockite, and other phosphates on a fracture surface that cuts a lithiophyllite nodule altered by strongly oxidizing, low-temperature.
It is found associated with Lithiophilite, lithiophosphate, collinsite, fairfieldite, whitlockite.
The mineral was named to honor mineralogist T. Scott Ercit (b. 1957) of the Canadian Museum of Nature, Ottawa, Ontario, Canada for his contributions to the mineralogy of granitic pegmatites.