Cancrinite – Saint-Hilaire

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Cancrinite crystals - click for larger pic
Cancrinite crystals
Photo by Doug Merson
© Doug Merson

NaCa(AlSi₂₄)(CO · 2H

Cancrinite is relatively common at MSH.

PHYSICAL CHARACTERISTICS:

Color is usually colorless to pale violet on smaller crystals, pale
to dark violet on larger crystals, and pale to dark yellow and
pale orange on fibrous masses.
Luster is vitreous on smaller crystals, dull to greasy on larger
crystals and dull on fibrous masses.
Diaphaneity is transparent in smaller crystals, and opaque in larger
crystals and fibrous masses.
Crystal System is hexagonal;
Crystal Habits include fibrous columnar masses several centimeters
across; crude prisms to 2cm; sharp prismatic crystals to 20mm
showing two sets of hexagonal sets terminated by hexagonal pyramid
and embedded spherical nodules of radiating prisms to 5mm.
Cleavage {010} is perfect and {001} is poor.
Fracture is uneven.
Hardness is 5 – 6.
Specific Gravity is approximately 2.25 g/cm
Streak is white.
Associated Minerals include amphibole group, biotite, fluorite,
phlogopite, rinkite and sérandite.
Distinguishing Features: Crystal habit and color.
Origin: Named in 1839 for Count Georg Cancrin (Egor Frantsevich
Kankrin)(1774-1845), Russian Minister of Finance.

CLASSIFICATION:

Dana System
# 76.2.5.3

Strunz Classification
# VIII/J.9-10

REFERENCES:
MinRec 21:301 (1990), Dana 8: 1634-1635 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
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