THE MINERAL MANGANITE
- Chemical Formula: MnO(OH), Manganese Oxide Hydroxide
- Class: Oxides and Hydroxides
- Uses: A minor source of manganese and as a mineral specimen
Specimens
PHYSICAL CHARACTERISTICS:
- Color is black to steel gray.
- Luster is metallic to dull in weather specimens.
- Transparency: Crystals are opaque, translucent in only thin splinters.
- Crystal System is monoclinic; 2/m
- Crystal Habit is typically short prismatic crystals that have a psuedo-orthorhombic shape. The terminations are generally blunted with domes and minor pyramid faces. The crystals are striated lengthwise. Crystals are usually grouped into tight bundles and columnar, massive and fiberous forms are also known. Penetration and contact twinning does occassionally occur.
- Cleavage is perfect in one direction lengthwise and good to fair in two other directions, one lengthwise at near right angles to the first one and one basal.
- Fracture is uneven.
- Hardness is 4
- Specific Gravity is 4.3 (average for metallic minerals)
- Streak is reddish to brownish black.
- Associated Minerals are calcite,
barite , garnets, limonite, siderite, pyrolusite and other manganese minerals. - Other Characteristics: Alters to pyrolusite which can coat the crystals, dulling the luster and can affect a streak test.
- Notable Occurrences include Cornwall, England; Harz Mts., Germany; China; Sterling Hill, New Jersey and Negaunee, Michigan, USA and Ukraine.
- Best Field Indicators are crystal habit, luster, striations, color and streak.
 Amethyst Galleries' Mineral Gallery MINERALS |
MANGANITE specimen man-1
$ 60.00
$ 60.00
Dims: 4-1/4" x 2" x 2"
Wt: 11.7 oz
Caland Pit, Atikokan, Ontario, Canada
This heavy specimen reminds me of a druse of black Dolomite on a brown-black matrix. The crystals are small, reaching no more than 3/16 inch square. Their luster is waxy and dull, and they seem to rest upon a base of massive Manganite, with possibly some botryoidal Goethite. I've not seen this mineral before we obtained this piece- from what I've read, it's not very common.
man-1 ($ 60.00)
Caland Pit, Atikokan, Ontario, Canada
MANGANITE specimen man-2
$ 55.00
$ 55.00
Dims: 2-1/4" x 1-1/8" x 1-1/4"
Wt: 2.31 oz
Caland Pit, Atikokan, Ontario, Canada
For a small specimen, this piece has disproportionately large Manganite crystals; the largest is over 1/2" long and almost 1/2" in diameter! All are clean and show little damage, and tend to lay low, erupting at angles that are close to being parallel to the matrix. All are black colored, with a bright, submetallic luster, and many show bending and curving along their lengths. Each has a very complex basal termination that can look almost rounded in instances. Hugging the small amount of visible matrix is a bed of tiny quartz crystals that add contrast and an extra sparkle to the piece.
man-2 ($ 55.00)
Caland Pit, Atikokan, Ontario, Canada
MANGANITE specimen man-3
$ 70.00
$ 70.00
Dims: 2-1/8" x 1-3/4" x 1-1/2"
Wt: 2.54 oz
Caland Pit, Atikokan, Ontario, Canada
Though possessing very small Manganite crystals, this Canadian specimen has hundreds of them! As a matter of fact, there is one tiny spot of matrix material that I can see on the piece; it's almost pure Manganite! The crystals form a crust on one part of the specimen that is almost 1/2 " thick, and they seem to average about 1mm in diameter! They have the black color and bright, submetallic luster characteristic of their locality's yield. One will get the most Manganite in this specimen.
man-3 ($ 70.00)
Caland Pit, Atikokan, Ontario, Canada
MANGANITE specimen man-4
$ 55.00
$ 55.00
Dims: 2.5" x 1.1" x 1.1"(6.4 x 2.8 x 2.8 cm)
Wt: 1.97 oz.(56.0 g) w/ base
Caland Pit, Atikokan, Ontario, Canada
This specimen is made up completely of Manganite, in very large crystals that have an odd shape. They possess the dark gray color and submetallic luster that is standard for this mineral, and are, of course, opaque. They range in size from 0.3 - 0.5"(0.8 - 1.3 cm) and seem to have compact, fibrous tendencies, but I believe that this is due to the fact that their normally flattened terminations are divided into many fine points. Every crystal seems to have grown tangental to the base of massive manganite, so that one of the prism edges is always buried. Thus, if a complete crystal were isolated, it would have a two-sided, leaf-shaped cross-section. It is affixed to a square acrylic base.
man-4 ($ 55.00)
Caland Pit, Atikokan, Ontario, Canada
MANGANITE specimen man-5
$ 100.00
$ 100.00
Dims: 2.5" x 2.0" x 1.8"(6.4 x 5.1 x 4.6 cm)
Wt: 7.95 oz.(225.4 g)
Caland Pit, Atikokan, Ontario, Canada
Though this specimen is mostly Manganite by weight, only a small part of its surface area is coated with crystals. They appear quite small, but actually make up a crust that is about 0.2 - 0.3"(5 - 8 mm) thick, depending on their lengths. Examination of the edges of this crust shows their radial habit. The crystals are colored black, have a submetallic luster, and are opaque. Part of the Manganite cluster is covered by a cluster of stubby, colorless quartz crystals that have excellent form and luster, and are mostly transparent. Both the quartz and Manganite crystals rest on a bed of more massive Manganite.
man-5 ($100.00)
Caland Pit, Atikokan, Ontario, Canada
MANGANITE specimen man-6
$ 27.00
$ 27.00
Dims: 1.7 x 1.3 x 0.8" (4.3 x 3.3 x 2.0 cm)
Wt: 2.15 oz. (61.1 g)
Caland Pit, Antikoken, Ontario, Canada
A cluster of heavily-intergrown Manganites rests on the manganese oxide base of this thumbnail specimen. The cluster has visible dimensions of 0.6 x 0.6 x 0.2" (1.5 x 1.5 x 0.5 cm) and is made up of several crystals that reach a maximum length of 0.3" (8 mm) and are in good condition- one is visibly damaged. Their monoclinic prismatic form appears nearly pseudo-hexagonal, and all have a gray-black color and a metallic, sub-adamantine luster. They are separated from their oxide base by a thin druse of tiny, colorless and transparent quartz crystals. The piece is hot-glued onto an acrylic base.
man-6 ($ 27.00)
Caland Pit, Antikoken, Ontario, Canada
MANGANITE specimen man-7
$ 40.00
$ 40.00
Dims:1.5x0.9x0.4" (3.8x2.3x1.0 cm)
Wt: 0.5oz. (15g)
Calland Pit, Atikokan, Ontario, Canada
This specimen consists of a crust of velvety manganite crystals on a massive manganite matrix with a minor amount of quartz. These crystals occur in sheaves, reaching 0.2" (0.5cm) in length. The only damage to this specimen is on the edges, and this is very minor.
man-7 ($ 40.00)
Calland Pit, Atikokan, Ontario, Canada
MANGANITE specimen man-8$ 450.00
Dims: 3.4x2.6x2.8" (8.8x6.7x7.1 cm)
Wt: 20.35 oz. (576 g)
Caland Open Pit Mine, Atikokan, Ontario, Canada
This unusual hand specimen of manganite looks like a geode, although it merely a cavity in the host rock which is lined in manganite crystals. This specimen is nearly all manganite, and the crystals in the protected cavity show a course fibrous appearance. On the outside of the specimen, this fibrous pattern gives portions of the surface a silky luster, very reminiscent of smithsonite. The manganite crystals are black and opaque, yet their luster is very bright, and more reflective than merely "metallic". There is only a small amount of host rock on the specimen, plus some tiny undamaged prismatic quartz crystals inside the cavity.
man-8 ($450.00)Caland Open Pit Mine, Atikokan, Ontario, Canada
MANGANITE specimen man-9
$ 32.00
$ 32.00
Dims: 2.17x1.85x1.02" (5.5x4.7x2.6cm)
Wt: 2.25oz (63.6g)
Khorate Mine, Morocco
Thin veins of manganite crystals are exposed on this brown host rock. The crystals are a metallic gray, and are arranged as flat radial clusters of shiny crystals, some of which approach 20mm in length. For the most part, the visible crystals are actually assemblages of even smaller acicular crystals. The over-all optical effect is pleasing.
man-9 ($ 32.00)
Khorate Mine, Morocco