Outstanding brown crystals of the rare mineral hilairite from the type locality: Mont Saint Hilaire, Québec, Canada. Hilairite is a zirconium mineral. — Photo: David Hospital · CC BY-SA 4.0
Hilairite
Hilairite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂ZrSi₃O₉·3H₂O.
It crystallizes in the hexagonal crystal system (space group R32).
Key properties: Mohs hardness 4; specific gravity 2.724; White streak; Vitreous to porcelaneous luster; optically uniaxial.
IMA symbol Hlr, IMA status: approved, named in 1972.
Found in miarolitic cavities and altered pegmatite dikes in nepheline syenite in an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada).
It is found associated with Catapleiite, elpidite, gaidonnayite, aegirine, analcime, albite, microcline, chlorite, calcite, epididymite, natrolite, fluorite, pyrite, sphalerite.
The name is derived from the locality at Mont Saint-Hilaire, Quebec, Canada.