Charmarite Locality: Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada FOV 3.0 x 3.3 mm Ex Jean-Pierre Beckerich. MOB coll. This specimen was illustrated in Lapis (10/98 p. 42) and Rivista (7-9/00 p. 151). This is a fairly narrow and relatively deep little cavity that is difficult to illuminate all at once. — Photo: Modris Baum · Public domain
Charmarite
Charmarite is an IMA-recognized mineral species in the carbonate class, with the chemical formula Mn₄Al₂(OH)₁₂(CO₃)·3H₂O.
It crystallizes in the hexagonal crystal system (space group P6_322). It is a member of the Hydrotalcite structural group.
Key properties: Mohs hardness 3; specific gravity 6.3–6.49; White streak; Adamantine luster; optically biaxial.
IMA symbol Char, IMA status: approved, named in 1992.
Found in the oxidized zone of a lead-bearing U–V deposit (Mounana mine, Gabon).
It is found associated with Francevillite, wulfenite (Mounana mine, Gabon).
The mineral was named to honor Jean Chervet (1904–1962), French mineralogist.