Cancrinite
Cancrinite is a feldspathoid mineral that often occurs alongside sodalite.
Fine crystalline specimens are rare, and the mineral is typically found in a granular massive form.
Information about Cancrinite
Cancrinite is a sodium calcium aluminium silicate carbonate mineral and a feldspathoid – one of the minerals that crystallise in alkaline igneous rocks that are too silica-poor to form feldspar, filling the same structural role that feldspar fills in normal granites and syenites but with a fundamentally different chemistry.
It is the defining species of the cancrinite group, and though it is relatively rare compared to the common feldspathoids nepheline and leucite, it is a conspicuous and beautiful mineral at the localities where it occurs well: pale yellow to orange-yellow, orange, or pale blue masses with a greasy to vitreous lustre, typically forming large anhedral masses in nepheline syenite.
It typically forms as anhedral to subhedral masses intergrown with nepheline, sodalite, and other feldspathoids in alkaline igneous rocks; occasionally as prismatic crystals with hexagonal cross-sections.
The colour ranges from colourless through pale yellow, orange-yellow, cream, and pale blue to lilac, with the orange and yellow varieties being most characteristic. The lustre is vitreous to greasy and the mineral has one perfect cleavage direction.
Uses and History
Cancrinite has no significant industrial applications and no gemological uses. It is collected as a mineral specimen and as part of the alkaline igneous rock mineral suite.
The mineral was first described from specimens collected in the Ural Mountains of Russia, and named in honour of Count Georg von Cancrin (12 November 1774 – 9 September 1845), Minister of Finance of the Russian Empire under Tsar Nicholas I from 1823 to 1844.
The best collector specimens come from the Ice River complex in British Columbia, Canada; Litchfield in Kennebec County, Maine, USA; and the Bancroft area of Ontario, Canada, where orange-yellow cancrinite occurs in large masses in nepheline syenite. Quality micros can be found in the Laacher See volcanic complex of Germany. The Dennis Hill locality in Maine provides some fine yellow specimens.
No significant British occurrences are on record.
Mineralogy
Hazards and Warnings
No specific health risks are associated with cancrinite under normal handling conditions.
Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis. When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.
Translations
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Hindi:
Portuguese:
- Cancrinita
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English:
- Cancrinite
Italian:
- Cancrinite
Russian:
- Канкринит
French:
- Cancrinite
Japanese:
- カンクリン石
Spanish:
- Cancrinita
German:
- Cancrinit
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Mandarin Chinese:
- 钙霞石
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