Hibonite
Current inventory:  0 gems
 

  
Hibonite was named after Paul Hibon who discovered the mineral in Madagascar in 1956.

Discovered in 1956;   IMA status:  Valid (pre-IMA; Grandfathered)

Chemistry

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

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/C.08-30

Nickel-Strunz 10th Ed. ID:

4.CC.45

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
C : With large and medium-sized cations

Related to:

Magnetoplumbite (Plumboferrite) Group

Members of Group:

Magnetoplumbite Group: Barioferrite, Batiferrite, Haggertyite, Hawthorneite, Hibonite, IMA2009-027, Magnetoplumbite, Nežilovite, Plumboferrite, Yimengite

Varieties:

None

Synonyms:

None

Crystal Data

Crystallography:

Hexagonal - Dihexagonal Dipyramidal

Crystal Habit:

Prisms, platy on {0001}, or steep pyramidal, to 4 cm, showing six sectors on {0001}.

Twinning:

None

Physical Properties

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)

Optical Properties

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

Occurances

Geological Setting:

In metamorphosed limestone, pyroxenite, gneiss, and granulite of the amphibolite to granulite facies; also alluvial. A common accessory in Ca–Al-rich inclusions in some carbonaceous chondrites.

Common Associations:

Calcic Plagioclase, Corundum, Spinel, Thorianite, Titanite (Esiva, Madagascar); Anorthite, Grossular, Titanite, Zoisite, Clinozoisite (Mahenge, Tanzania); Vesuvianite, Hercynite, Corundum, Andalusite, Kyanite, Diopside, Rutile, Titanite, Magnetite (Shoriya Mountains, Russia).

Common Impurities:

Fe, Si

Type Locality:

Esiva eluvials, Maromby Commune, Amboasary District, Anosy Region (Fort Dauphin Region), Tuléar Province (Toliara), Madagascar

Year Discovered:

1956

View mineral photos:

Hibonite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Hibonite is an extremely rare gem. Mineral specimens are rarely large enough or transparent enough for faceting. Hibonite crystals found in Madagascar and Russia are relatively large but are opaque dark brown or black. A few very small crystals were found West of Mogok, Myanmar in 2011. The exact location is Tha-Yet-Pin-Pyint, near Ka-Pine, West of Mogok, Myanmar. These crystals have good reddish-brown color and are occassionally transparent enough to be faceted but are small. Most of the crystals are kept for mineral specimens so very few were made available for faceting. It is believed that only about 10 faceted gems exist. The Spring 2011 issue of Gems and Gemology features a photo and write-up of gem Hibonite.

Hibonite was named after Paul Hibon who discovered the mineral in the Esiva eluvials, 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 is the largest carbonaceous chondrite ever found on Earth. The meterorites fall to Earth was witnessed on February 8, 1969, falling over the Mexican state of Chihuahua near Pueblito de Allende. After breaking up in the atmosphere, an extensive search for pieces was conducted and it is often described as "the best-studied meteorite in history". The Allende meteorite is notable for possessing abundant, large calcium-aluminium-rich inclusions, which are among the oldest objects formed in the Solar System. Hibonite-Fe found in this meteorite is said to be blue in color.

Distribution: From Esiva, near Taolänaro (Fort Dauphin), and near Ambindandrakemba, Madagascar. In Tanzania, in the Furura granulite complex, southwest of Mahenge. In the Esiva eluvials, 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 several other less-well-defined places in Russia. From Punalur, Kerala, India. Noted in some carbonaceous chondrite meteorites, as Allende, Murchison, etc.
 

  
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