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| Hollandite
is named for Dr. Thomas Henry Holland (1868-1947), Director
of the Indian Geological Survey.
| Discovered
in 1906;
IMA
status: Valid (pre-IMA; Grandfathered) |
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Chemistry
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Chemical
Formula: |
Ba(Mn4+,Mn2+)8O16
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Barium
Manganese Oxide |
Molecular
Weight: |
852.99 gm |
Composition: |
Barium |
12.88 % |
Ba |
14.38 % |
BaO |
|
Sodium |
0.27 % |
Na |
0.36 % |
Na2O |
|
Manganese |
42.51 % |
Mn |
4.16 % |
MnO
/ 62.17% MnO3 |
|
Aluminum |
0.63 % |
Al |
1.20 % |
Al2O3 |
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Iron |
8.51 % |
Fe |
12.17 % |
Fe2O3 |
|
Silicon |
0.33 % |
Sii |
0.70 % |
SiO2 |
|
Lead |
4.86 % |
Pb |
5.23 % |
PbO |
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Oxygen |
30.01 % |
O |
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|
|
100.00 % |
|
100.38 % |
= TOTAL OXIDE |
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Classification
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Mineral
Classification: |
Oxides
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Strunz 8th
Ed. ID:
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4/D.08-60
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Nickel-Strunz 10th
Ed. ID:
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4.DK.05
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4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar K : With large (+- medium-sized) cations; tunnel structures
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Related
to: |
Cryptomelane
Group
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Crystal
Data
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Crystallography:
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Monoclinic
- Prismatic
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Crystal
Habit:
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Crystals
short prismatic with flat pyramidal termination, to
several em; radial fibrous, massive.
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Twinning:
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Common
on {101}
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Physical
Properties
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Cleavage: |
Distinct/Good,
Prismatic
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Tenacity:
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Brittle
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Moh's
Hardness: |
4.7
- 6.0; VHN
= 488-560 || [001], 620-689 - [001] (100 g load)
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Density:
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4.95 (g/cm3)
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Luminescence:
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None
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Radioactivity:
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Not
Radioactive
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Optical
Properties
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Color: |
Black,
Grayish Black to Silvery Gray
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Transparency: |
Opaque
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Luster: |
Metallic,
Earthy (Dull)
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Refractive
Index: |
R1-R2:
(400) 31.3-37.7, (420) 31.2-37.4, (440) 31.1-37.1, (460)
30.5-36.5, (480) 29.7-35.9, (500) 29.1-35.0, (520) 28.5-34.2,
(540) 27.8-33.1, (560) 27.1-32.2, (580) 26.6-31.5, (600)
26.3-30.9, (620) 26.1-30.4, (640) 25.8-30.0, (660) 25.6-29.5,
(680) 25.3-29.0, (700) 25.0-28.4; Biaxial
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Birefringence: |
0.000
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Dispersion: |
n/a
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Pleochroism: |
Weak
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Anisotrophism: |
Strong;
color in reflected light: White
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Occurances
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Geological
Setting: |
A
primary mineral in contact metamorphic manganese ores,
and a secondary weathering product of earlier manganese-bearing
minerals. |
Common
Associations: |
Bixbyite,
Braunite, Piemontite, other manganese oxides |
Common
Impurities: |
Fe,
Pb, K, Na |
Type
Locality: |
Kajlidongri mine, Jhabua District, Madhya Pradesh, India
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Year
Discovered: |
1906
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View
mineral photos: |
Hollandite
Mineral Photos and Locations |
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More
Information
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|
Mindat.org Webmineral.com
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Hollandite
is a silvery-gray to black mineral composed of barium and
manganese. It occurs as opaque crystals and massive
material but the interest in this mineral in the gem
trade is as inclusions in
Quartz gems.
It forms beautiful radiating black "stars"
throughout quartz crystals coming from Madagascar. These
well formed Quartz crystals are collected by mineral
collectors and rarely faceted into gems prominantly
diplaying the attractive Hollandite stars.
Hollandite
is found in these locations: in India, at Kajlidongri
and Sitapar, Chhindwara district, Madhya Pradesh; in
the Nagpur and Balaghat districts, Maharashtra; at Banswara,
Rajasthan; and elsewhere. From Sorharras, Ultevis, Sweden.
In Norway, from Tangen, Hurdal. At Langenberg, Saxony,
Germany. From Inken, Tiovine region, Morocco. In the
USA, in the Artillery Mountains, Mohave County, and
in the Apache mine, Sierra Ancha district, Gila County,
Arizona. As fine inclusions in Quartz from Madagascar.
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Hollandite
gems for sale:
We
have not photographed our Hollandite gems. Please
check back soon.
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