Scheuchzerite
Scheuchzerite is a recently discovered hydroxyvanadosilicate mineral that was found at the Fianel Mine, Ausserferrera, Ferrera Valley, Hinterrhein Valley, Grischun, Switzerland in 2004. It forms yellow-orange, transparent, radiating, acicular crystals up to 0.8 mm in the matrix. Scheuchzerite was named for the Swiss naturalist Johann Jakob Scheuchzer (1672-1733), junior physician of the city of Zürich, curator of the Kunstkammer – a cabinet of natural history and curiosities. He held the chair of physics and mathematics, University of Zürich. He did much work on Swiss geology and mineralogy that was essential for his time. Scheuchzerite mineral specimens and gems are rare.
Locations for finding Scheuchzerite: the type locality (TL) Fianel Mine, Ausserferrera, Ferrera Valley, Hinterrhein Valley, Grischun (Grisons; Graubünden), Switzerland; Valgraveglia Mine (Gambatesa Mine), Reppia, Graveglia Valley, Ne, Genova Province, Liguria, Italy.
| Chemical Formula: | Na(Mn,Mg,Zn)9[VSi9O28(OH)](OH)3 |
| Hydroxy Sodium Manganese Magnesium Zinc Silicate Vanadate (hydroxyvanadosilicate) | |
| Emperical Chemical Formula: | Na0.97(Mn7.79Mg0.95Zn0.16Ni0.04Ca0.03Al0.01)∑=8.98(V0.95As0.02Si9.08)∑=10.05O32.05H4 |
| Molecular Weight: | 1,309.36 gm |
| Composition: | Sodium | 1.70 % | Na | 2.30 % | Na2O |
| Calcium | 0.09 % | Ca | 0.13 % | CaO | |
| Magnesium | 1.76 % | Mg | 2.92 % | MgO | |
| Manganese | 32.69 % | Mn | 42.20 % | MnO | |
| Aluminum | 0.02 % | Al | 0.04 % | Al2O3 | |
| Vanadium | 3.70 % | V | 6.60 % | V2O5 | |
| Zinc | 0.80 % | Zn | 0.99 % | ZnO | |
| Silicon | 19.48 % | Si | 41.67 % | SiO2 | |
| Nickel | 0.18 % | Ni | 0.23 % | NiO | |
| Arsenic | 0.11 % | As | 0.18 % | As2O5 | |
| Hydrogen | 0.31 % | H | 2.75 % | H2O | |
| Oxygen | 39.16 % | O | |||
| 100.00 % | 100.01 % | = TOTAL OXIDE |
| Crystallography: | Triclinic – Pinacoidal |
| Crystal Habit: | Forms yellow-orange, transparent, radiating acicular prismatic crystals up to 0.8 mm |
| Twinning: | None |
| Cleavage: | Distinct/good parallel to [111] (parallel to fiber elongation) |
| Fracture: | n/a |
| Tenacity: | Brittle |
| Moh’s Hardness: | 2.5 |
| Density: | 3.50 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Yellow-orange |
| Transparency: | Transparent |
| Luster: | Vitreous |
| Refractive Index: | 1.740 – 1.750 Biaxial ( + ) |
| Birefringence: | n/a |
| Dispersion: | n/a |
| Pleochroism: | Weak; x = brown yellow, y = pale yellow |
