Cancrinite

cancrinite

sodalite

natrolite

nepheline

Images

Formula: Na,Ca,☐)8(Al6Si6)O24 (CO3,SO4)2.2H2O
Tectosilicate (framework silicate), feldspathoid
Specific gravity:
Hardness: 5 to 6
Streak: White
Colour: Grey-green, white, yellow, blue, orange, reddish
Solubility: It is unusual among the silicate minerals in that it is moderately soluble in hydrochloric acid due to the carbonate ions in its structure.
Common impurities: Ti,Fe,Mg,K,Cl,S
Environments:

Plutonic igneous environments
Pegmatites
Metamorphic environments

Cancrinite is a primary mineral in some alkaline igneous rocks, including pegmatites in nepheline syenite. It is also an alteration product of nepheline in igneous rocks (HOM). Associated minerals include andradite, monticellite, natrolite, nepheline, orthoclase, zircon and sodalite (Mindat, HOM).

Localities

At Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Quebec, Canada, cancrinite pseudomorphs after natrolite have been found with rhodochrosite (KL p265).

The type locality is the Ilmen Nature Reserve, Chelyabinsk Oblast, Russia.

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