About Cancrinite
For Count Egor Frantsevich Kankrin (Georg Cancrin) (16 November 1774 – 10 September 1845), Russian Minister of Finance.
Cancrinite hand-specimen
Formula: (Na,Ca,[])8(Al6Si6O24)(CO3,SO4)2 • 2H2O
System: Hexagonal
Color: Especially yellow; grey-green, white, blue, orange, reddish
Lustre: Vitreous, Greasy, Pearly
Hardness: 5–6
Density: 2.42–2.51
System: Hexagonal
Color: Especially yellow; grey-green, white, blue, orange, reddish
Lustre: Vitreous, Greasy, Pearly
Hardness: 5–6
Density: 2.42–2.51
XPL
PPL
Cancrinite #1 thin section (hFOV 2mm)
XPL
PPL
Cancrinite #2 thin section (hFOV 2mm)
![[thumb]](http://microckscopic.ro/wp-content/uploads/cancrinite_4_02-150x150.jpg)
![[thumb]](http://microckscopic.ro/wp-content/uploads/cancrinite_01-150x150.jpg)
Cancrinite PPL properties
Relief: Low negative
Habit/Form: Crystals are doubly terminated hexagonal prisms. Also commonly found as anhedral or subhedral grains.
Color: Colorless; sometimes pale yellow in grain mount
Pleochroism: –
Cleavage: Basal sections show three cleavages intersecting at 60° angle. Cleavage fragments and longitudinal sections show only one cleavage.
Habit/Form: Crystals are doubly terminated hexagonal prisms. Also commonly found as anhedral or subhedral grains.
Color: Colorless; sometimes pale yellow in grain mount
Pleochroism: –
Cleavage: Basal sections show three cleavages intersecting at 60° angle. Cleavage fragments and longitudinal sections show only one cleavage.
Cancrinite XPL properties
Isotropy/Anisotropy: Anisotropic
Interference color: Order I-II
Extinction angle: Parallel / 0° / straight to crystal outlines and/or cleavage traces.
Twins: Rare, lamellar
Uniaxial/Biaxial: Uniaxial (+/-)
Optic axial angle (2V): –
Interference color: Order I-II
Extinction angle: Parallel / 0° / straight to crystal outlines and/or cleavage traces.
Twins: Rare, lamellar
Uniaxial/Biaxial: Uniaxial (+/-)
Optic axial angle (2V): –
Cancrinite distinguishing features under the microscope
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References
- Deer, W. A., Howie, R. A., & Zussman, J. (2013). An introduction to the rock-forming minerals (pp. 498). Mineralogical Society of Great Britain and Ireland, London.
- mindat.org – The Mineral Database
