Brucite
Current inventory:  0 gems
 

  
Brucite is named after Archibald Bruce (1777–1818), physician and early American mineralogist, Professor at the College of Physicians and Surgeons (later Columbia University), New York, New York, USA, who first described the species.

Discovered in 1824;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Mg(OH)₂

Magnesium Hydroxide

Molecular Weight:

58.32 gm

Composition:

Magnesium

41.68 %

Mg

69.11 %

MgO

Hydrogen

3.46 %

H

30.89 %

H₂O

Oxygen

54.87 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/F.03-10

Nickel-Strunz 10th Ed. ID:

4.FE.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
E : Hydroxides with OH, without H₂O; sheets of edge-sharing octahedra

Related to:

Brucite Group.

Members of Group:

Brucite Group: Amakinite, Brucite, Pyrochroite, Portlandite, Theophrastite

Varieties:

Manganbrucite, Nemalite

Synonyms:

Amianthoid Magnesite, Amianthus, Hydrate of Magnesia, Monoklinoëdrisches Magnesiahydrat, Native Magnesia, Shepardite (of Brooke), Texalite

Crystal Data

Crystallography:

Trigonal - Hexagonal Scalenohedral

Crystal Habit:

Crystals rare, tabular, to 19 cm, in platy or foliated masses and rosettes; also fibrous, to 50 cm; granular, massive.

Twinning:

None

Physical Properties

Cleavage:

Perfect on {0001}

Fracture:

Sectile, separable plates are flexible; Fibrous, fibers are elastic.

Tenacity:

Brittle

Moh's Hardness:

2.5 - 3.0

Density:

2.39 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Pyroelectric

Optical Properties

Color:

White, pale Green, Blue, Gray; Honey-Yellow to Brownish Red and deep Brown in manganoan varieties

Transparency:

Transparent to Translucent

Luster:

Vitreous to Waxy; Pearly on cleavages

Refractive Index:

1.56 - 1.60  Uniaxial ( + ); anomalously Biaxial

Birefringence:

0.0200

Dispersion:

None

Pleochroism:

None

Occurances

Geological Setting:

A common alteration of periclase in marble; a low-temperature hydrothermal vein mineral in metamorphic limestones and chlorite schists; formed during serpentinization of dunites.

Common Associations:

Aragonite, Artinite, Calcite, Chrysotile, Dolomite, Hydromagnesite, Magnesite, Talc

Common Impurities:

Fe, Mn, Zn

Type Locality:

Castle Point, Hoboken, Hudson Co., New Jersey, USA

Year Discovered:

1824

View mineral photos:

Brucite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Brucite is a very rare oxide mineral that is rarely formed as crystals. It is usually found as fibrous, granular or massive. The rare crystals are usaully small and only translucent. Beautiful pale green crystals have been found at Tsumeb, Namibia. Brucite is a mineral that is not often used as a mineral specimen but does have some important industrial uses. It is a minor ore of magnesium metal and a source of magnesia.

Brucite is found in many localities, but rarely in crystalline masses. In the USA, at Hoboken, Hudson County, New Jersey; large crystals from Wood’s Chrome mine, near Texas, Lancaster County, Pennsylvania; at the Tilly Foster mine, Brewster, Putnam County, New York; a large deposit near Gabbs, Gabbs district, Nye County, Nevada; at the Crestmore quarry, Riverside County, California. In Canada, at Asbestos and Wakefield, Quebec. From Mt. Vesuvius, Campania, and at Teulada, Sardinia, Italy. On Unst, Shetland Islands, and at Camas Mòr, Isle of Muck, Scotland. At Långban and Nordmark, Värmland, Sweden. From Asbest, Ural Mountains, Russia. Fine crystals in the Ethyl mine, Mutorashanga, Zimbabwe. From Phalaborwa, Transvaal, South Africa. Fine crystals also found in Namibia at the Kombat Mine, Grootfontein District, Otjozondjupa Region; and the Tsubeb Mine, Tsumeb, Otjikoto Region.
 

  
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