Seraphinite
Seraphinite is a trade name for a particular form of clinochlore, a member of the chlorite group. Seraphinite apparently acquired its name due to its resemblance to feathers due to its chatoyancy. Seraphinite is named after the biblical seraphs or seraphim angels.[1] With some specimens the resemblance is quite strong, with shorter down-like feathery growths leading into longer “flight feathers”; the resemblance even spurs fanciful marketing phrases like “silver plume seraphinite.” Seraphinite is generally dark green to gray in color, has chatoyancy, and has hardness between 2 and 4 on the Mohs scale of mineral hardness.
Seraphinite is mined in a limited area of eastern Siberia in Russia. Russian mineralogist Nikolay Koksharov (1818-1892 or 1893) is often credited with its discovery. It occurs in the Korshunovskoye iron skarn deposit in the Irkutskaya Oblast of Eastern Siberia.
| Chemical Formula: | (Mg,Fe2+)5Al(Si3Al)O10(OH)8 |
| Magnesium Iron Aluminum Silicate Hydroxide | |
| Molecular Weight: | 595.22 gm |
| Composition: | Magnesium | 15.31 % | Mg | 25.39 % | MgO |
| Aluminum | 9.07 % | Al | 17.13 % | Al2O3 | |
| Iron | 11.73 % | Fe | 15.09 % | FeO | |
| Silicon | 14.16 % | Si | 30.28 % | SiO2 | |
| Hydrogen | 1.35 % | H | 12.11 % | H2O | |
| Oxygen | 48.38 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | In thin to thick pseudohexagonal crystals, with tapering pyramidal faces, to 10 cm. Commonly foliated, fibrous, granular, earthy, massive. |
| Twinning: | Twin plane {001}; twin axis [310], composition plane {001}. |
| Cleavage: | {001} Perfect |
| Fracture: | Uneven |
| Tenacity: | Laminae Flexible, Inelastic |
| Moh’s Hardness: | 2.0 – 2.5 |
| Density: | 2.60 – 3.02 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Blackish Green, Bluish Green, White, Yellowish Green, or Olive Green |
| Transparency: | Transparent to Translucent |
| Luster: | Greasy, Pearly, Dull |
| Refractive Index: | 1.571 – 1.599 Biaxial ( + ) |
| Birefringence: | 0.005 – 0.011 |
| Dispersion: | r < v |
| Pleochroism: | Visible; X= light yellow green to light blue-green, Y=Z= light greenish yellow to light blue-green |
