Hibonite
Hibonite is a treasure that is extremely unusual. Mineral specimens are rarely large transparent or enough for faceting. Hibonite crystals discovered in Madagascar and Russia are relatively big but are opaque dark black or brown. A few extremely crystals that are little found West of Mogok, Myanmar in 2011. The place that is exact Tha-Yet-Pin-Pyint, near Ka-Pine, West of Mogok, Myanmar. These crystals have a good color that is reddish-brown are occasionally clear sufficient to be faceted but are small. Most of the crystals are kept for mineral specimens so hardly any were made available for faceting. It is believed that only about 10 gems that are faceted. The Spring 2011 issue of Gems and Gemology includes a write-up and photo of gem Hibonite.
Hibonite was named after Paul Hibon who discovered the mineral in the Esiva eluvial, Amboasary District, Anosy Region (Fort Dauphin Region), Tuléar Province, Madagascar in 1956.
Hibonite is closely related to Hibonite-Fe (IMA 2009-027) an alteration mineral from the Allende meteorite. The Allende meteorite could be the largest chondrite that is carbonaceous found on Earth. The meteorite’s fall to Earth was witnessed on February 8, 1969, dropping on the state that is Mexican of near Pueblito de Allende. An extensive search for pieces was carried out and it is often referred to as “the best-studied meteorite in history” after separating in the environment. The Allende meteorite is notable for possessing abundant, big inclusions which are calcium-aluminum-rich which are on the list of oldest objects formed in the Solar System. Hibonite-Fe found in this meteorite is said to be blue in color.
Circulation: From Esiva, near Taolänaro (Fort Dauphin), and near Ambindandrakemba, Madagascar. In Tanzania, within the Furura granulite complex, southwest of Mahenge. Within the Esiva eluvial, Maromby Commune, Amboasary District, Anosy Region (Fort Dauphin Region), Tuléar Province (Toliara), Madagascar. In the Shoriya Mountains, about 400 km southeast of Novosibirsk, western Siberia, and lots of other less-well-defined places in Russia. From Punalur, Kerala, India. Noted in certain carbonaceous meteorites that are chondrite as Allende, Murchison, etc.
| Category: | Oxide minerals |
| Chemical Formula: | (Ca,Ce,La)(Al,Ti,Mg,Fe)12O19 |
| Calcium Cerium Lanthanum Aluminum Titanium Magnesium Iron Oxide | |
| Molecular Weight: | 708.81 gm |
| Composition: | Calcium | 4.52 % | Ca | 6.33 % | CaO |
| Lanthanum | 1.96 % | La | 2.30 % | La2O3 | |
| Cerium | 1.98 % | Ce | 2.32 % | Ce2O3 | |
| Magnesium | 0.17 % | Mg | 0.28 % | MgO | |
| Titanium | 3.38 % | Ti | 5.63 % | TiO2 | |
| Aluminum | 39.59 % | Al | 74.80 % | Al2O3 | |
| Iron | 5.52 % | Fe | 7.10 % | FeO | |
| Oxygen | 42.89 % | O | |||
| 100.00 % | 98.76 % | = TOTAL OXIDE |
| Crystallography: | Hexagonal – Dihexagonal Dipyramidal |
| Crystal Habit: | Prisms, platy on {0001}, or steep pyramidal, to 4 cm, showing six sectors on {0001}. |
| Twinning: | None |
| Cleavage: | Good on {0001}; parting on {1010} |
| Fracture: | Sub-Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 7.5 – 8.0 |
| Density: | 3.84 (g/cm3) |
| Luminescence: | Not Fluorescscent |
| Radioactivity: | Mild; GRapi = 4,081.56 (Gamma Ray American Petroleum Institute Units) |
| Color: | Brownish black to black; reddish brown in thin fragments; blue in meteorites. |
| Transparency: | Semitransparent to Opaque |
| Luster: | Vitreous |
| Refractive Index: | 1.790 – 1.807 Uniaxial ( – ) |
| Birefringence: | 0.00 |
| Dispersion: | n/a |
| Pleochroism: | O = brownish gray; E = gray |
