Lemoynite Locality: Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire , Rouville RCM, Montérégie , Québec , Canada ( Locality at mindat.org ) Picture width 3 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Lemoynite
Lemoynite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂CaZr₂Si₁₀O₂₆·5-6H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Lemoynite structural group.
Key properties: Mohs hardness 4; specific gravity 2.29; Vitreous luster; optically biaxial.
IMA symbol Lmo, IMA status: approved, named in 1968.
An uncommon mineral, in pegmatite in an intrusive alkalic gabbro-syenite complex (Mpnt Saint-Hilaire, Canada); in miarolytic cavities in a nepheline syenite sill (near Saint-Amable, Canada).
It is found associated with Sodalite, nepheline, eudialyte, catapleiite, elpidite, zircon, microcline (Mont Saint-Hilaire, Canada); albite, natrolite, zakharovite, aegirine, eudialyte.
The name refers to Charles Lemoyne (1625–1685), Lord of Longuevil, and his four sons, well-known personalities in French-Canadian history.