THE MINERAL BIXBYITE

  • Chemical Formula: (Mn, Fe)2O3, Manganese Iron Oxide
  • Class: Oxides and Hydroxides
  • Uses: A minor ore of manganese and as mineral specimens.
  • Specimens

Bixbyite is a rare mineral, but is still well known among collectors. It forms well formed isometric crystals, usually highly modified cubes. It also is associated with several interesting and attractive minerals and has a nice high luster. For these reasons bixbyite is popular among collectors although it only has an unimpressive black color and the crystals are usually small less than 1 centimeter wide.

The associated minerals include pink and clear topaz, pink beryl, spessartine, quartz, hematite, hausmannite, braunite and pseudobrookite. These assortments are found in cavities in rhyolitic rock and make for attractive and much sought after mineral specimens. Especially wonderful bixbyite specimens come from the Thomas Range in Utah.

The crystals of bixbyite are usually cubes. The corners can be modified by octahedral faces which truncate the corners with a single flat face. Also the faces of a dodecahedron can be seen modifying just the corners of the predominant cube with three faces per corner. If all three forms are present the crystal can look rather complex and beautiful.

As an ore of manganese, bixbyite is often under appreciated. When found massive, it is usually associated with other manganese oxides and is impossible to differentiate. Although iron can substitute for the manganese in the structure by over 50%, many bixbyite samples are nearly pure manganese oxide.

PHYSICAL CHARACTERISTICS:

  • Color is dark black.
  • Luster is metallic to submetallic.
  • Transparency crystals are opaque.
  • Crystal System is isometric; 2/m bar 3
  • Crystal Habits include cubes often with octahedral and dodecahedral faces modifying the corners. Also as massive and granular.
  • Cleavage is octahedral.
  • Fracture is uneven.
  • Hardness is 6.5
  • Specific Gravity is 4.9 - 5.0 (slightly above average for metallic minerals)
  • Streak is black.
  • Associated Minerals include beryl, quartz, spessartine, hematite, pseudobrookite, hausmannite, braunite and topaz.
  • Notable Occurrences are limited to the Thomas Range, Utah; San Luis Potosi, Mexico; northern Patagonia, Argentina; Gerona, Spain; India; Sweden and South Africa.
  • Best Field Indicators are crystal habit, density, hardness, associations and locality.
BIXBYITE specimens:
(hover for more info)
BIXBYITE specimen bix-1
$ 30.00
Dims: 0.8" x 0.6" x 0.2" (2.0 x 1.5 x 0.5 cm)
Wt: 11.3 g w/ specimen box
Thomas Range, Juab County, Utah, U.S.A.
This tiny specimen consists of an incomplete Bixbyite cube attached to a small amount of a chalky, cream-colored host rock. Though not complete, the cube shows no human-induced damage and has excellent form, with well-defined edges and smooth faces that have a bright, metallic luster. It has a dark gray color and is, of course, completely opaque. It is held inside a cube-shaped specimen box with an adhesive putty.
no photo
bix-1 ($ 30.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-2
$ 35.00
Dims: 0.9" x 0.7" x 0.5" (2.3 x 1.8 x 1.3 cm)
Wt: 5.0 g
Thomas Range, Juab County, Utah, U.S.A.
This relatively simple thumbnail specimen consists of a lone Bixbyite crysal that is resting on a pale gray host. It is undamaged and measures nearly 0.2" (4 mm) along each of its axes. It has a dark, gray-black coloration that is almost indicative of galena. The crystal has excellent cubic form, with sharp edges and clean faces that show a metallic luster. Its form is not perfect, though, as it was interrupted due to intergrowth with a topaz crystal. There are at least 4 discernable topazes visible on the piece, but none are complete; they are all missing their terminations, which seem to have been cleaved cleanly off. They have the standard pale beige coloration and vitreous luster, and are tranparent and show considerable clarity. They partially extend out of the pale, chalky host rock. The specimen is affixed inside a plastic specimen box with adhesive putty.
no photo
bix-2 ($ 35.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-3
$ 25.00
Dims: 0.8" x 0.6" x 0.4" (2.0 x 1.5 x 1.0 cm))
Wt: 13.2 g w/ specimen box
Thomas Range, Juab County, Utah, U.S.A.
At least 12 separate and distinct Bixbyite cubes are visible on this thumbnail specimen. These cubes range in diameter from less than 1 mm up to 0.1" (3 mm) and are generally in very good condition, showing only minor damage to their edges and corners. All have excellent form, with sharp edges and smooth, clean faces that possess a bright, submetallic luster. Like all Bixbyites, these crystals are black in color and opaque. According to our documentation, they rest on a base of hematite that pseudomorphed after garnet. I do not really see this in the specimen, but this "pseudomorph" in turn rests on a base that consists of an incomplete topaz crystal. The piece is affixed inside a plastic specimen box with an adhesive putty.
no photo
bix-3 ($ 25.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-4
$ 30.00
Dims: 2.4 x 2.0 x 1.0" (6.1 x 5.1 x 2.5 cm)
Wt: 2.08 oz. (59.0 g)
Thomas Range, Juab County, Utah, U.S.A.
Scores of Bixbyite cubes rest in an on the chalky, cream-colored host rock of this specimen. Only 2 of these crystals, however, exceed 1 mm in diameter. The smaller of these two shows some slight damage, but the larger is intact and in excellent condition. This large crystal measures 0.2" (5 mm) in diameter and like its smaller counterpart, has excellent cubic form, with well-defined edges, clean faces, and small secondary faces that truncate some of its corners. Both have the classic black-gray coloration and submetallic luster of their species. They are accompanied by a few small topaz crystals that are comparable in size and are likewise in very good condition. A few tiny pseudobrookites are also scattered about the host rock.
no photo
bix-4 ($ 30.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-5
$ 40.00
Dims: 0.6 x 0.5 x 0.5" (1.5 x 1.3 x 1.3 cm)
Wt: 8.6 g w/ base
Thomas Range, Juab County, Utah, U.S.A.
The rhyolite host of this thumbnail specimen is littered with small Bixbyite crystals. These crystals do not exceed 0.1" (3 mm) in diameter but are in excellent condition, showing almost no damage. Their cubic form is excellent, and all have the dark gray-black color and semi-metallic luster of their species. The piece is affixed to a flat acrylic base with an adhesive putty.
no photo
bix-5 ($ 40.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-6
$ 40.00
Dims: 0.7 x 0.6 x 0.6" (1.8 x 1.5 x 1.5 cm)
Wt: 10.5 g w/ base
Thomas Range, Juab County, Utah, U.S.A.
At least 20 tiny Bixbyite crystals rest on the rhyolite base of this thumbnail specimen. These crystals are in excellent condition and do not exceed 0.1" (3 mm) in diameter. Their cubic form is likewise excellent, with well-defined edges and clean faces. All have the standard gray-black color and sub-metallic luster. The piece is affixed to a flat acrylic base with an adhesive putty.
no photo
bix-6 ($ 40.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-7
$ 38.00
Dims: 0.9 x 0.6 x 0.5" (2.3 x 1.5 x 1.3 cm)
Wt: 13.0 g
Thomas Range, Juab County, Utah, U.S.A.
Ten or more Bixbyite crystals rest on the rhyolite host rock of this thumbnail specimen. These crystals are quite small, not exceeding 0.1" (3 mm) in diameter. They are generally in good condition and have excellent cubic form. They have the standard gray-black color and dull metallic luster of their species. A single, small topaz crystal accompanies them on the rhyolite, which is affixed to a flat acrylic base with an adhesive putty.
no photo
bix-7 ($ 38.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-8
$ 25.00
Dims: 1.3 x 1.1 x 0.6" (3.3 x 2.8 x 1.5 cm)
Wt: 8.3 g
Thomas Range, Juab County, Utah, U.S.A.
This thumbnail specimen consists of two intersecting Bixbyite cubes that rest on a rhyolite base. The cubes do not exceed 0.1" (3 mm) in diameter, and though one shows light damage along one edge, the other is undamaged and in excellent condition. Both have the standard gray-black color and submetallic luster of their species, and rest upon what appears to be a "nodule" of topaz intermixed with rhyolite, which in turn rests on the rhyolite base. When viewed from above, this "nodule" has a rounded triangular shape. I have seen a few of these formations before, but I don't know what causes them.
no photo
bix-8 ($ 25.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-9
$ 28.00
Dims: 0.5 x 0.3 x 0.3" (1.3 x 0.8 x 0.8 cm)
Wt: 7.0 g w/ base
Thomas Range, Juab County, Utah, U.S.A.
This small thumbnail specimen consists of a cluster of intersecting Bixbyite crystals that rests on a small rhyolite protrusion. These do not quite reach 0.2" (5 mm) in diameter but are in excellent condition, showing almost no damage. All have excellent cubic form and show the gray-black color and submetallic luster that are common for the species. The piece is affixed to an octagonal acrylic base with an adhesive putty.
no photo
bix-9 ($ 28.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-10
$ 32.00
Dims: " ( cm)
Wt: g w/ base
Thomas Range, Juab County, Utah, U.S.A.
A single Bixbyite crystal rests on the rhyolite base of this thumbnail piece. It measures about 0.2" (5 mm) in diameter and is in excellent condition, showing one small spot of light damage. Its cubic form is likewise excellent, and it has a gray-black color and a submetallic luster. The piece is affixed to an octagonal acrylic base with an adhesive putty.
no photo
bix-10 ($ 32.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-11
$ 36.00
Dims: 0.9 x 0.4 x 0.3" (2.3 x 1.0 x 0.8 cm)
Wt: 8.1 g w/ base
Thomas Range, Juab County, Utah, U.S.A.
This interesting thumbnail specimen consists of 5 or 6 Bixbyite cubes that are partly embedded in a topaz crystal. The cubes do not exceed 0.1" (3 mm) but are in excellent condition and have excellent form. All have the standard gray-black color and submetallic luster, though most are dulled somewhat by tiny crusts of rhyolite. The topaz crystal is also in good condition and has moderately good form due to heavy rhyolite inclusions. It has a pale brown color but is only transparent at its termination, due to the aforementioned rhyolite. The piece is affixed to an octagonal acrylic base with an adhesive putty.
no photo
bix-11 ($ 36.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-12
$ 30.00
Dims: 1.5 x 0.8 x 0.7" (3.8 x 2.0 x 1.8 cm)
Wt: 10.9 g w/ base
Thomas Range, Juab County, Utah, U.S.A.
The rhyolite host of this specimen holds a single Bixbyite cube that is in excellent condition and has near-perfect form. It does not measure more than 0.2" (5 mm) along an edge and has the classic gray-black color and submetallic luster of the species. The rhyolite base on which it rests also holds several tiny hematite blades- though these blades are misshapen, they are generally undamaged. The piece is affixed to an octagonal acrylic base with an adhesive putty.
no photo
bix-12 ($ 30.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-13
$ 25.00
Dims: 0.3 x 0.3 x 0.2" (8 x 8 x 5 mm)
Wt: 8.9 g w/ specimen box
Thomas Range, Juab County, Utah, U.S.A.
This small thumbnail specimen consists of a single Bixbyite cube that is partly embedded in a bit of rhyolite host rock. The cube is in excellent condition, showing no human-induced damage, and has good form, though most of its edges are notched in places. Its gray-black color and submetallic luster are standard for the specie. The piece is hot-glued inside a plastic specimen box.
no photo
bix-13 ($ 25.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-14
$ 25.00
Dims: 0.2 x 0.2 x 0.2" (5 x 5 x 5 mm)
Wt: 9.2 g w/ specimen box
Thomas Range, Juab County, Utah, U.S.A.
A small Bixbyite cube to which is attached a few bits of rhyolite host rock comprises this specimen. The cube is in excellent condition, showing no human-induced damage, and has moderately good form, as it is incomplete and most of its edges are naturally notched. It has the standard gray-black color and submetallic luster, and is affixed inside a plastic specimen box.
no photo
bix-14 ($ 25.00)
Thomas Range, Juab County, Utah, U.S.A.
BIXBYITE specimen bix-15
$ 28.00
Dims: 0.24x0.20x0.20" (0.6x0.5x0.5cm)
Wt: 5.10ct (1.02g)
Thomas Range, Juab County, Utah, USA
This is a relatively large crystal of bixbyite, measuring about 5mm on a side. It is black, opaque, and the surface has a vitreous luster (but is somewhat dulled by very light pitting). Nearly all of the "nicks" seen on the edges and corners are actually growth patterns - only a few are actual damage, revealed by the shiny fracture surfaces. The cube is not perfect, and is not quite complete, as a tiny bit of the host rock is still present.
no photo
bix-15 ($ 28.00)
Thomas Range, Juab County, Utah, USA
BIXBYITE specimen bix-16
$ 60.00
Dims: 0.51x0.45x0.42" (1.29x1.13x1.08cm)
Wt: 0.15oz (4.3g)
Juab County, Utah, USA
This aesthetic specimen consists of a single large cube of bixbyite with nearly a dozen tiny prismatic crystals of topaz. The bixbyite is a nearly perfecty proportioned cube, it is black, opaque, and has a vitreous luster. There are several pits or missing edges or corners which appear due to obstruction from surounding minerals. The golden topaz crystals are tiny and transparent, mostly growing directy on the bixbyite. The result is one of my favorite bixbyite specimens. It has been glued to a piece of styrofoam which may be difficult to remove.
no photo
bix-16 ($ 60.00)
Juab County, Utah, USA

 


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