• Chemistry: (Mn+2)(Mn+3)2O 4 , Manganese Oxide
  • Class: Oxides
  • Uses: a minor ore of manganese and as a mineral specimen.
  • Specimens

Hausmannite is usually not a beautiful mineral; however some specimens are truly wonderful. It can have a bright metallic luster and form well-shaped crystals. The crystals are tetragonal dipyramids, an eight faced form that looks psuedo-octahedral. Indeed at first look, good crystals of hausmannite appear to be octahedrons like those formed by the spinel group of minerals. The formula of hausmannite, (Mn+2)(Mn+3)2O 4, would also seem to place it in the spinel group. Their general formula is AB2 O4, where A can be a manganese with a positive two charge and B can be a manganese with a positive three (+3) charge. However, those A and B positions are filled with other elements when either one has a manganese ion present. Both sites can not accommodate a manganese ion at the same time and still preserve the isometric structure. Ergo, hausmannite has a distorted spinel structure that produces a tetragonal symmetry and a basal cleavage not possible in the spinel group of minerals. At much higher temperatures, the structure of hausmannite converts to the isometric spinel structure. Hausmannite is an interesting, and can be (when well-formed) a first-rate mineral specimen.


  • Color is dark brown or black.
  • Luster is submetallic to metallic.
  • Transparency: crystals are opaque.
  • Crystal System: tetragonal; 4/m 2/m 2/m
  • Crystal Habits: include the pseudo-octahedral tetragonal dipyramid. Minor pyramidal faces may truncate only the top and bottom points, giving evidence of its tetragonal symmetry instead of the isometric octahedron. Twinning is common and repeated. Also granular and massive.
  • Cleavage is perfect in one direction, basal.
  • Fracture is uneven.
  • Hardness is 5.5
  • Specific Gravity is 4.8+ (average for metallic minerals)
  • Streak is brown.
  • Associated Minerals include psilomelane, pyrolusite, Bixbyite and other manganese minerals.
  • Other Characteristics: dipyramid faces might be horizontally striated (not possible on an octahedron).
  • Notable Occurrences include Batesville, Arkansas, USA; Ilfeld, Germany; Langban, Sweden and the Ural Mountains, Russia.
  • Best Field Indicators are crystal habit, color, hardness, cleavage, density and locality.
HAUSMANNITE specimens:
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HAUSMANNITE specimen hau-1
$ 25.00
Dims: 3/4" x 1/2" x 1/2"
Wt: 3.5 g
N'Chwaning Mine, Kuruman, South Africa
The first piece of Hausmannite that I've ever seen, this lovely little thumbnail is made up of about 5 visible crystals, and a bit of small crystal portions. The largest of these crystals measures approx. 5/16 inch in diameter, and all occur in well-formed pseudo-octahedrons that are not quite symmetrical. Their faces and edges are reasonably clean, with noticeable striations, and their color is a basic black with a waxy, almost submetallic luster.
no photo
hau-1 ($ 25.00)
N'Chwaning Mine, Kuruman, South Africa
HAUSMANNITE specimen hau-3
$ 100.00
Dims: 1.3" x 1.2" x 0.7"(3.3 x 3.0 x 1.8 cm)
Wt: 1.21 oz.(34.4 g)
N'Chwaning Mine, Kuruman, South Africa
Over 10 pseudo-octahedral Hausmannite crystals rest on one side of this South African specimen. They range in size from 2 - 8 mm along an edge, and have the black color, bright submetallic luster, and opacity of Hausmannite from this locality. Though they have a rough form and seem to possess considerable damage, they are quite attractive and retain a definitely crystalline structure. They rest amid several heavily cleaved calcite crystals. The opposite side of the specimen contains dozens of smaller, intergrown Hausmannite crystals, many of which are damaged and incomplete. Together, they make up a sparkly black crust that coats the face. The specimen is glued to an acrylic base with a hot-wax.
no photo
hau-3 ($100.00)
N'Chwaning Mine, Kuruman, South Africa
HAUSMANNITE specimen hau-4
$ 40.00
Dims: 0.9" x 0.6" x 0.5"(2.3 x 1.5 x 1.3 cm)
Wt: 14.2 g w/ base
N'Chwaning Mine, Kuruman, South Africa
Many intergrown pseudo-octahedrons of Hausmannite make up the bulk of this specimen. They range in size from less than 0.1 to 0.3"(2 - 8 mm) along an edge, and have the black color, bright submetallic luster and opacity of Hausmannite. Although heavy intergrowth has warped the crystals, eliminating their regular shapes, their form is good and definitely crystalline. A small amount of calcite accompanies the cluster, and the specimen is hot-glued to a square acrylic base.
no photo
hau-4 ($ 40.00)
N'Chwaning Mine, Kuruman, South Africa
HAUSMANNITE specimen hau-5
$ 180.00
Dims: 2.3" x 1.6" x 1.2" (5.8 x 4.1 x 3.8 cm)
Wt: 3.40 oz. (96.4 g)
N'Chwaning Mine, Hotazel, Kuruman, South Africa
One of the largest of these specimens that we could find, this piece is made up mostly of Hausmannite by weight. Though much of its surface is rough and shows no semblance of crystal form, there are many areas that show excellent pseudo-octahedral crystals, though all are incomplete due to their intergrowth. The largest visible crystal shows only three of its triangular faces, and these are incomplete. However, the most complete one measures nearly 0.6 along an edge (see the close-up image). Their size then decreases down to a little over 1 mm in any dimension. All have the standard black color and almost metallic, vitreous luster that is common for this mineral. They are, needless to say, opaque. Several of the more exposed crystals show considerable damage in the form of broken or abraded corners and edges. There is also a small cluster of milky-white calcites on one area of its surface- these are mostly broken, so that their initial crystal form is hard to determine.
no photo
hau-5 ($180.00)
N'Chwaning Mine, Hotazel, Kuruman, South Africa
HAUSMANNITE specimen hau-6
$ 110.00
Dims: 0.9" x 0.7" x 0.6" (2.3 x 1.8 x 1.5 cm)
Wt: 15.1 g w/ base
N'Chwaning Mine, Hotazel, Kuruman, South Africa
This small thumbnail specimen contains some of the odder and more beautiful Hausmannite crystals that I think we have had available. There are at least 7 distinct crystals present on the specimen, though 4 of them are heavily intergrown, but all are in excellent condition and show no visible damage. The largest of these crystals measures 0.4 x 0.4 x 0.3" (1.0 x 1.0 x 0.8 cm), and is one of the several that are intergrown. Though I am unsure, I think that this multiple intergrowth has something to do with twinning. Most of the crystals have the standard tetragonal pseudo-octahedral form, but there is one that is long and slender, with a seemingly prismatic form! I think that this crystal's form also has something to do with twinning. All of them are colored black and have a bright, adamantine luster. They are held together by a matrix of white, crystalline calcite, and the piece is hot-glued onto a square acrylic base.
no photo
hau-6 ($110.00)
N'Chwaning Mine, Hotazel, Kuruman, South Africa
HAUSMANNITE specimen hau-7
$ 50.00
Dims: 1.5" x 1.5" x 1.0" (3.8 x 3.8 x 2.5 cm)
Wt: 1.7 oz. (47.4 g)
New N'Chwaning Mine, Hotazel, Kuruman, South Africa
Most of this small specimen's mass is made up of Hausmannite, in the form of a large cluster of heavily intergrown crystals. These crystals reach a diameter of 0.5" (1.3 cm) and are generally in very good condition, as only a very small amount of damage is visible to the cluster. All have reasonably good tetragonal, pseudo-octagonal form, with well-defined edges and heavily-patterned but easily definable faces that show the standard adamantine luster. They have a black coloration and are completely opaque. Among this cluster are small crusts of tiny, sparkling red crystals. These crystals are made up of a variety of garnet, but I am not sure which variety. The base on which these crystals rest is likely made up of finely-grained, massive Hausmannite.
no photo
hau-7 ($ 50.00)
New N'Chwaning Mine, Hotazel, Kuruman, South Africa
HAUSMANNITE specimen hau-8
$ 60.00
Dims: 1.1 x 0.8 x 0.4" (2.8 x 2.1 x 1.0 cm)
Wt: 17.80 g w/ specimen box
N'Chwaning Mine, Kuruman, South Africa
A partly-cut crust of intergrown Hausmannite crystals makes up this thumbnail specimen. These crystals do not exceed 0.2" (4 mm) in diameter but are generally in very good condition and have excellent tetragonal, pseudo-octahedral form. All have the standard gray-black color and bright metallic/adamantine luster. Scattered on the crust are also several tiny, red garnets- unfortunately, I do not know to what specie they belong. The piece is affixed inside a plastic specimen box with a hot-glue.
no photo
hau-8 ($ 60.00)
N'Chwaning Mine, Kuruman, South Africa
HAUSMANNITE specimen hau-9
$ 65.00
Dims:1.2x1.2x0.6" (3.0x3.0x1.5 cm)
Wt: 0.6oz. (16g)
Kuruman, South Africa
The matrix rock of this thumbnail specimen is covered with a layer of white calcite crystals. These in turn are covered with a layer of black, pseudooctahedral hausmannite crystals. These hausmannite crystals range in size up to 0.2" (0.5cm). The only damage to this specimen is on the edges, where it was pried away from the host rock. The black crystals on the white background makes for an aesthetic combination.
no photo
hau-9 ($ 65.00)
Kuruman, South Africa
HAUSMANNITE specimen hau-10
$ 60.00
Dims: 2.34x1.55x1.69" (5.95x3.93x4.30cm)
Wt: 4.99oz (141.3g)
N'Chwaning Mine, South Africa
This is a very nice specimen of hausmanite, even though it does not display large crystals. The form is botryoidal (or perhaps stalactitic), without a visible growth pattern. The surface texture is most interesting - it has a dull, matte appearance, but under a loupe it appears composed of tiny balls with a rough yet sparkly luster. The color is a dark gray. The bottom of the specimen has many crystal faces, but unfortunately they belonged to an underlying crystal cluster, since disolved away. I have not guessed what that might have been, although the imprints suggest long, prismatic, tapering hexagonal crystals.
no photo
hau-10 ($ 60.00)
N'Chwaning Mine, South Africa


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