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| Norbergite
is named from the locality
where it was discovered; Norberg, Sweden.
| Discovered
in 1926;
IMA
status: Valid (pre-IMA; Grandfathered) |
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Chemistry
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|
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Chemical
Formula: |
Mg3(SiO4)(F,OH)2 |
|
Magnesium
Silicate Fluoride Hydroxide |
Molecular
Weight: |
202.00 gm
|
Composition: |
Magnesium |
36.10 % |
Mg |
59.86 % |
MgO |
|
Silicon |
13.90 % |
Si |
29.74 % |
SiO2 |
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Hydrogen |
0.25 % |
H |
2.23 % |
H2O |
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Oxygen |
35.64 % |
O |
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Fluorine |
14.11 % |
F |
14.11 % |
F |
|
- |
-
% |
F |
-5.94 % |
-O=F2 |
|
|
100.00 % |
|
100.00 % |
= TOTAL OXIDE |
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Classification
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Mineral
Classification: |
Silicates (Germanates)
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Strunz 8th
Ed. ID:
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8/B.04-10
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Nickel-Strunz 10th
Ed. ID:
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9.AF.40
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9 : SILICATES (Germanates)
A : Nesosilicates F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
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Related
to: |
Humite
Group.
|
Members
of Group: |
Humite
Group: Alleghanyite,
Chegemite, Chondrodite, Clinohumite, Edgrewite, Humite, Hydroxylchondrodite,
Hydroxylclinohumite, Jerrygibbsite, Kumtyubeite, Leucophoenicite,
Manganhumite, Norbergite, Reinhardbraunsite, Ribbeite,
Sonolite
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Varieties: |
None
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Synonyms: |
Grothine
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Crystal
Data
|
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Crystallography:
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Orthorhombic
- Dipyramidal
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Crystal
Habit:
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Crystals
rare, to 2.5 cm, thick tabular, typically rounded and
highly modified; granular.
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Twinning:
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None
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Physical
Properties
|
|
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Cleavage: |
[???]
Distinct
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Fracture: |
Irregular/Uneven
to Sub-Conchoidal
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Tenacity:
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Brittle
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Moh's
Hardness: |
6.0
- 6.5
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Density:
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3.177 (g/cm3)
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Luminescence:
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May
fluoresce tan-yellow to canary-yellow under SW UV light.
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Radioactivity:
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Not
Radioactive
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Optical
Properties
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Color: |
Tan,
Yellow, Yellow-Orange, Orange-Brown, Pink with Purplish
tint, White; pale Yellow to Colorless in thin section
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Transparency: |
Transparent
to Translucent
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Luster: |
Vitreous
to Resinous
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Refractive
Index: |
1.563
- 1.593 Biaxial ( + )
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Birefringence: |
0.0270
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Dispersion: |
Slight
to Strong; r > v
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Pleochroism: |
X
= pale yellow; Y
= very pale yellow; Z
= colorless
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Occurances
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Geological
Setting: |
In
contact metamorphic zones in limestones and dolostones
into which plutonic rocks or pegmatites have introduced
fluorine. |
Common
Associations: |
Calcite,
Cuspidine, Dolomite, Fluoborite, Fluorite, Forsterite,
Grossular, Ludwigite, Monticellite, Phlogopite, Tremolite,
Wollastonite |
Common
Impurities: |
Ti,
Al, Fe, Mn, Zn, Ca, H2O
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Type
Locality: |
Östanmoss mine, Norberg, Västmanland, Sweden
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Year
Discovered: |
1926
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View
mineral photos: |
Norbergite
Mineral Photos and Locations |
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More
Information
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|
Mindat.org
Webmineral.com
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Norbergite
is a rare member of the Humite Group of minerals that
includes
Chondrodite,
Clinohumite, Humite and Norbergite. It is one of several rare minerals that
have been found at the famous mines at Franklin, New
Jersey, USA. It is also one of the many fluorescent
minerals found there. It will glow tan to canary-yellow
under SW UV. It is often found associated with other
fluorescing minerals such as red fluorescing
Calcite
and blue fluorescing
Diopside.
The combination of different fluorescing colors can be quite attractive. Norbergite
rarely forms as transparent crystals but mostly as tiny
translucent to opaque
crystals or granular masses. Therefore, Norbergite is
only suitable for cabochons.
There
are only a few locations for finding Norbergite, at
the Type Locality of Östanmoss mine, Norberg, Västmanland, Sweden;
Mogok, Sagaing District, Mandalay Division, Burma (Myanmar);
San Vito quarry, San Vito, Ercolano, Monte Somma, Somma-Vesuvius Complex, Naples Province, Campania, Italy;
Near Loch Ness, Inverness-shire, Scotland, in the USA
at Franklin, Franklin Mining District, Sussex County, New Jersey;
Limecrest Quarry, Sparta Township, Sussex Co., New Jersey.
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Norbergite
gems for sale:
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Gem:
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Norbergite
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Stock
#:
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NORB-001
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Weight:
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38.3510
ct |
Size: |
37.66
x 25.62 x 5.91 mm |
Shape: |
Triangular
Cabochon |
Color: |
Tan,
Yellow, White, Black |
Clarity: |
Opaque
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Origin: |
Franklin,
New Jersey, USA |
Treatment: |
None
(natural) |
Price: |
$76.00
[
Make an offer ]
|
Pictures
are of the actual gem offered for
sale. Gem images are magnified to
show detail. |
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This rare
gem is from the Franklin, New Jersey,
USA area famous for fluorescent minerals.
The bottom picture shows the gem under
short wave UV light with the Norbergite
glowing yellow.
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