Högbomite (Magnesiohögbomite-2N2S)
Current inventory: 0 gems
 

  
Högbomite was named in 1916 by Axel Olof Gavelin in honor of Arvid Gustav Högbom (1857-1940), professor of mineralogy and geology, University of Uppsala, Sweden.

Discovered in 1916; IMA status: Valid (pre-IMA; Grandfathered) (IMA Approved 19)

Chemistry

Chemical Formula:

(Mg,Fe²⁺)₂(Al,Ti)₅O₁₀

Magnesium Iron Aluminum Titanium Oxide

Molecular Weight:

423.03 gm

Composition:

Magnesium

3.45 %

Mg

5.72 %

MgO

Titanium

3.40 %

Ti

5.66 %

TiO₂

Aluminum

31.89 %

Al

60.26 %

Al₂O₃

Zinc

3.09 %

Zn

3.85 %

ZnO

Iron

17.16 %

Fe

16.98 %

FeO / 5.66 % Fe₂O₃

Hydrogen

0.17 %

H

1.49 %

H₂O

Oxygen

40.85 %

O

100.00 %

99.62 %

= TOTAL OXIDE

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/C.07-

Nickel-Strunz 10th Ed. ID:

4.CB.20

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

Related to:

Högbomite Group. Polymorphism: 4H, 5H, 6H, 8H, 15H, 15R, 18R, 24R polytypes, polytypoids.

Members of Group:

Högbomite Group: Ferrohögbomite-2N2S, Ferrohögbomite-6N12S, Magnesiohögbomite-2N2S, Magnesiohögbomite-2N3S, Magnesiohögbomite-2N4S, Zincohögbomite-2N2S, Zincohögbomite-2N6S 

Varieties:

None

Synonyms:

Hoegbomite, Högbomite-4H

Crystal Data

Crystallography:

Hexagonal - Dihexagonal Pyramidal

Crystal Habit:

Rare crystals are tabular, thin to thick, on {0001}, to 5 mm; commonly granular, massive, intergrown and included with other species.

Twinning:

On {0001}, may be repeated; on {h0hl}, probable 

Physical Properties

Cleavage:

Imperfect on {0001}, another on {h0hl}, may be partings

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

6.5; Vickers: VHN₁₀₀=1064 - 1216 kg/mm²

Density:

3.81 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Weakly magnetic

Optical Properties

Color:

Black; brown in transmitted light; gray in reflected light

Transparency:

Opaque, transparent in thin fragments

Luster:

Adamantine

Refractive Index:

1.803 - 1.853  Uniaxial ( - )

Birefringence:

0.030 - 0.045

Dispersion:

n/a

Pleochroism:

Distinct; O = dark golden brown; E = light golden brown

Anisotropism:

Distinct

Occurances

Geological Setting:

A primary mineral, or replacing spinel or magnetite, in skarns, gabbros, gneisses, “emery” or other rocks formed during medium- to high-grade metamorphism; rarely detrital.

Common Associations:

Corundum, ferroan Spinel, Magnetite, Ilmenite, Rutile, Nigerite, Sapphirine, Sillimanite, Cordierite, Kyanite, Garnet, Quartz, Chlorite, Gedrite, Phlogopite

Common Impurities:

None

Type Locality:

Ruoutevare, Kvikkjokk, Lappland, Sweden

Year Discovered:

1916 (Högbomite); Magnesiohögbomite-2N2S IMA approved 1963

View mineral photos:

Magnesiohögbomite-2N2S Mineral Photos and Locations

Unusual Gem Categories

Black Gems, Magnetic Gems

More Information

Mindat.org (Högbomite)
Mindat.org (Magnesiohögbomite-2N2S)
Webmineral.com (Magnesiohögbomite-2N2S)

Högbomite was originally described by Axel Olof Gavelin in 1916 from material found at Ruoutevare, Kvikkjokk, Lappland, Sweden. It was named by Gavelin in honor of Arvid Gustav Högbom (1857-1940), professor of mineralogy and geology, University of Uppsala, Sweden. Högbomite was renamed Magnesiohögbomite-2N2S in 2002 according to the new Högbomite Group nomenclature approved by the IMA CNMMN (Commission on New Minerals and Mineral Names). Högbomite is now a group name comprised of seven members of similar chemistry but various dominant elements. The 2N2S refers to 2 Nolanite and 2 Spinel modules in its chemistry. The name Högbomite is also used synonymously with unspecified members of the Högbomite Group.

Högbomite is weakly magnetic, opaque and black with adamantine luster and often intergrown with Ilmenite and Pleonaste.

Högbomite distribution: in the Ruoutevare Fe–Ti deposit, near Kvikkjokk, Norrbotten, Sweden. At Rödstrand, Norway. From the Shoriya Mountains, western Siberia, Russia. At Cashal, near Toombeola, County Galway, Ireland. On Mautia Hill, Tanzania. At the Linganga deposit, Njombe district, Tanzania. From Tsaobis, Namibia. In the USA at Whittles, Pittsylvania County, Virginia; Peekskill, Westchester County, New York; and Franklin, Macon County, North Carolina. In the Romay mine, San Juan, Catamarca Province, Argentina. From the Strangways Range, Northern Territory, Australia. On the Prince Olav Coast, eastern Antarctica. More localities are known.
 

  
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