Charleshatchettite
A very rare hydrated calcium-niobium oxide from the famously mineral-rich Mont Saint-Hilaire in Québec.
Intro adapted from Wikipedia (CC BY-SA).
Charleshatchettite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula CaNb₄O₁₀(OH)₂·8H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: Mohs hardness 4; specific gravity 2.878; Silky luster; optically biaxial.
IMA symbol Chh, IMA status: approved, named in 2015.
A late-stage mineral, probably developed from a niobium-rich precursor on a fracture surface in fine-grained nepheline syenite.
It is found associated with Albite, quartz, muscovite, pyrrhotite, pyrite, ancylite-(Ce), siderite.
The mineral was named to honor Charles Hatchett (1765-1847), an English chemist who discovered niobium, a dominant element in charleshatchettite.