Anthoinite
AlWO3(OH)3 [CNMNC approved formula]
Named for Raymond Anthoine (1888-1971), Belgian mining engineer, who wrote on prospecting of alluvial deposits.
| IMA status : | Valid species (Pre-IMA 1947) Grandfathered |
| CLASSIFICATION | |
| Dana (8th edition) : |
48.03.03.01 |
| (48) Anhydrous Molybdates and Tungstates | |
| (48.03) (Basic Anhydrous) | |
| (48.03.03) | |
| Nickel-Strunz (10th edition) : |
07.GB.35 |
| (07) Sulfates (selenates, tellurates, chromates, molybdates, wolframates) | |
| (07.G) Molybdates, Wolframates and Niobates | |
| (07.GB) With additional anions and/or H2O | |
| Crystal system: | Triclinic System |
| Point group (H-M): | 1 — pinacoidal |
| Unit cell: | a = 8.196(1) Å, b = 9.187(1) Å, c = 11.316(1) Å α = 92.82(1)°, β = 94.08(1)°, γ = 90.23(1)° |
| Crystal Habit: | Crystals tabular, microscopic; chalk-like masses, pseudomorphs after scheelite |
| Color: | White (when free of iron) |
| Diaphaneity: | Translucent |
| Luster: | Earthy, dull |
| Hardness (Mohs): | 1 |
| Measured Density: | 4.8 g/cm3 |
| Cleavage: | 1; {001} perfect |
| Streak: | White |
| Geologic Setting: | In placers with cassiterite and wolframite and in quartz veins with ferberite, which appears to replace it (Mt. Misobo mine, Congo); in altered skarn (Kara mine, Tasmania). |
| Mineral Association: | Ferberite, scheelite (Mt. Misobo mine, Congo); mpororoite, scheelite (Kara mine, Tasmania); raspite, ferberite, ferritungstite (Gifurwe mines, Rwanda): ferberite, scheelite, ferritungstite, russellite, mpororoite (Kalzas Mountain, Canada) |
White platy anthoinite with brown ferritungstiteOrigin: Nyakabingu, Bumbogo, Rwanda
Sample size: 1 x 1.5 cm
Photo: Diederik Visser