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| Hodgkinsonite
is named for H.H. Hodgkinson, Assistant Underground
Superintendent of the Franklin mine, who discovered
the mineral.
| Discovered
in 1913. IMA
status: Valid (pre-IMA; Grandfathered) |
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Chemistry
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Chemical
Formula: |
Mn2+Zn2(SiO4)(OH)2
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Zinc
Manganese Silicate Hydroxide |
Molecular
Weight: |
311.82 gm
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Composition: |
Manganese |
17.62 % |
Mn |
22.75 % |
MnO |
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Zinc |
41.94 % |
Zn |
52.20 % |
ZnO |
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Silicon |
9.01 % |
Si |
19.27 % |
SiO2 |
|
Hydrogen |
0.65 % |
H |
5.78 % |
H2O |
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Oxygen |
30.79 % |
O |
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|
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.01-10
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Nickel-Strunz 10th
Ed. ID:
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9.AE.20
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9 : SILICATES (Germanates)
A : Nesosilicates E :
Nesosilicates with additional anions (O,OH,F,H2O); cations in
tetrahedral [4] coordination
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Related
to: |
Euclase
Group
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Varieties: |
n/a
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Synonyms: |
n/a
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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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As
euhedral crystals, stout prismatic and terminated by
steep pyramids, also dominated by pyramidal forms, to
2 cm. Granular to massive in veinlets.
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Twinning:
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None
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Physical
Properties
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Cleavage: |
Perfect
on {001}
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Fracture: |
Conchoidal
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Tenacity:
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Brittle
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Moh's
Hardness: |
4.5
- 5.0
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Density:
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4.06
- 4.08 (g/cm3)
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Luminescence:
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Not often
fluorescent, but some specimens have shown a red, weak
pink or dull dark purple fluorescence under longwave UV light.
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Radioactivity:
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Not
Radioactive
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Optical
Properties
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Color: |
Bright
Pink or Red to Reddish Brown and Orange, rarely Yellow;
Black from tarnish or inclusions.
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Transparency: |
Transparent,
Translucent to Opaque
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Luster: |
Vitreous
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Refractive
Index: |
1.720
- 1.746 Biaxial ( - )
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Birefringence: |
0.0260
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Dispersion: |
Strong
to moderate; r > v or r < v
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Pleochroism: |
Distinct;
in
shades of lavender and pale purple.
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Occurances
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Geological
Setting: |
As
seams in massive willemite-franklinite granular ore
in a metamorphosed stratiform zinc deposit (Franklin,
New Jersey, USA). |
Common
Associations: |
Barite,
Willemite, Franklinite, Tephroite, Pyrochroite, Calcite,
Manganoan Garnet, Copper. |
Common
Impurities: |
Fe,
Mg, Ca |
Co-Type
Localities: |
•
Franklin Mine, Franklin,
Franklin Mining District, Sussex County, New Jersey, USA • Hamburg Mine (Hamburg Road
Mine), Franklin, Franklin Mining District, Sussex County, New Jersey, USA |
Year
Discovered: |
1913
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View
mineral photos: |
Hodgkinsonite
Mineral Photos and Locations |
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More
Information
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Mindat.org
Webmineral.com
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Hodgkinsonite
is an extremely rare mineral and gem. Hodgkinsonite
is one of the rarest of all collector gems. It was discovered
in 1913 at the Franklin Mining District, Sussex County,
New Jeresey, USA. This is the only location for finding
Hodgkinsonite in the world. It is one of several minerals
found at this location and nowhere else. Hodgkinsonite
was mined out years ago and the mines have been closed.
Hodgkinsonite is the product of the metamorphism of
other zinc minerals such as Hemimorphite and
Smithsonite.
It is a very attractive mineral that is found in bright
pink to lavender colors. Gems can be very attractive
with colors of bright pink, red to reddish brown,
orange, or rarely yellow but are typically very small
due to small crystal sizes.
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Hodgkinsonite
gems for sale:
We
have not photographed our Hodgkinsonite gems
yet. Please
check back soon.
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