Cancrinite
Cancrinite is among the known people of the Feldspathoid band of minerals which includes Cancrinite, Haüyne, Lazurite, Leucite, Nepheline, and Sodalite. Minerals with chemistries that are near to those regarding the feldspars that are alkali but are poor in silica (SiO2) content are known as Feldspathoids. Although faceted gems which are cancrinite known to exist, they’re extremely rare and often tiny. Cabochons are also rare, but more common than faceted gems. Cabochons with the yellow or orange variety of Cancrinite and contrasting matrix that is black colored makes for a lovely cabochon, perhaps one of the most beautiful of gem cabochons.
Current sourced elements of Cancrinite are Bancroft, Ontario, Canada; Eifel Mountains, Germany; Kola Peninsula, Russia; Alnö, Sweden, and Litchfield, Maine, United States Of America.
| Category: | Feldspathoid |
| Chemical Formula: | Na6Ca2Al6Si6O24(CO3)2 |
| Sodium Calcium Aluminum Silicate Carbonate | |
| Molecular Weight: | 1,052.50 |
| Composition: | Sodium | 13.11 % | Na | 17.67 % | Na2O |
| Calcium | 7.62 % | Ca | 10.66 % | CaO | |
| Aluminum | 15.38 % | Al | 29.06 % | Al2O3 | |
| Silicon | 16.01 % | Si | 34.25 % | SiO2 | |
| Carbon | 2.28 % | C | 8.36 % | CO2 | |
| Oxygen | 45.60 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Hexagonal – Pyramidal |
| Crystal Habit: | Rarely as prismatic crystals, terminated by a low pyramid, to 2 cm; commonly massive. |
| Twinning: | Lamellar, rare |
| Cleavage: | Perfect on {1010}, Poor on {0001} |
| Fracture: | Irregular/Uneven |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.0 – 6.0 |
| Density: | 2.42 – 2.51 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Colorless, White, light Blue to light Grayish Blue, honey-Yellow, Orange, Reddish; Colorless in thin section |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous, Pearly or Greasy |
| Refractive Index: | 1.495 – 1.528 Uniaxial ( – ) or ( + ) |
| Birefringence: | 0.012 – 0.025 |
| Dispersion: | Weak |
| Pleochroism: | Colorless |
