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| Hardystonite
was named after Hardyston Township, Sussex County, New Jersey, USA, locality of
the Franklin orebody prior to incorporation of Franklin Borough in 1913.
Hardyston Township surrounds the borough of Franklin today.
| Discovered
in 1899;
IMA
status:
Valid (pre-IMA; Grandfathered) |
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Chemistry
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Chemical
Formula: |
Ca2ZnSi2O7
|
|
Calcium
Zinc Silicate |
Molecular
Weight: |
313.71 gm
|
Composition: |
Calcium |
25.55 % |
Ca |
35.75 % |
CaO |
|
Zinc |
20.84 % |
Zn |
25.94 % |
ZnO |
|
Silicon |
17.91 % |
Si |
38.31 % |
SiO2 |
|
Oxygen |
35.70 % |
O |
|
|
|
|
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:
|
8/C.02-40
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Nickel-Strunz 10th
Ed. ID:
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9.BB.10
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9 : SILICATES (Germanates)
B : Sorosilicates B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
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Related
to: |
Melilite
Group.
|
Members
of Group: |
Melilite
Group: Åkermanite,
Alumoåkermanite, Gehlenite, Gugiaite, Hardystonite,
Okayamalite
|
Varieties: |
None
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Synonyms: |
None
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Crystal
Data
|
|
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Crystallography:
|
Tetragonal
- Scalenohedral
|
Crystal
Habit:
|
In
coarse, columnar masses; granular and as isolated grains.
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Twinning:
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None
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Physical
Properties
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Cleavage: |
Good
on {001}, Poor on {100} and {110}
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Fracture: |
Irregular/Uneven
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Tenacity:
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Brittle
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Moh's
Hardness: |
3.0
- 4.0
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Density:
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3.396
- 3.443 (g/cm3)
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Luminescence:
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Fluorescent;
dull to dark purple under SW UV, blue to violet blue
under LW UV
|
Radioactivity:
|
Not
Radioactive
|
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Optical
Properties
|
|
|
Color: |
White,
pale pinkish, light brownish white, grayish white; colorless
in thin section.
|
Transparency: |
Translucent |
Luster: |
Vitreous,
Resinous, Dull |
Refractive
Index: |
1.657
- 1.672
Uniaxial ( - )
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Birefringence: |
0.011
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Dispersion: |
n/a |
Pleochroism: |
None
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Occurances
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Geological
Setting: |
In
granular ore in a metamorphosed stratiform zinc deposit.
|
Common
Associations: |
Vesuvianite,
Apatite, Franklinite, Willemite, Rhodonite, Calcite,
Dolomite |
Common
Impurities: |
Al,
Fe, Mn, Pb, Mg, Na
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Type
Locality: |
Franklin Mine, Franklin, Franklin Mining District, Sussex Co., New Jersey, USA
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Year
Discovered: |
1899
|
View
mineral photos: |
Hardystonite
Mineral Photos and Locations |
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More
Information
|
|
|
|
Mindat.org
Webmineral.com
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Hardystonite
is a calcium zinc silicate mineral that is usually a
dull, unattractive white color in natural daylight but
will fluoresce purple under short-wave (SW) ultraviolet
(UV) light and blue to violet blue under logn-wave (LW)
ultraviolet (UV) light. For this reason Hardystonite
is well known to collectors of fluorescent minerals
from Franklin and Sterling Hill, New Jersey. Fluorescence occurs when the ultraviolet light (invisible
to humans) imparts energy to some of the atoms in the mineral. This energy
is converted by the atom into visible light that we can then see.
Hardystonite
is often found in association with other fluorescent
minerals such as Calcite,
Clinoherderite, Esperite, Fluorite,
Willemite and
Wollastonite.
When two or more of these minerals are found together
in one specimen it can make for wonderfully colorful
fluorescent specimens. The purple or violet-blue
color of Hardystonite really stands out among these minerals.
Distribution:
From the type locality at Franklin Mine, Sussex County, New Jersey, USA.
At Vrchlice River valley, Policany, Kutna Hora, Central
Bohemian Region, Czech Republic. At Gottesbelohnung smelter,
Hettstedt, Mansfeld Basin, Saxony-Anhalt, German. At
Tsumeb, Otjikoto Region, Namibia. At Swietochlowice,
Katowice, Upper Silesia (Slaskie), Poland.
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Hardystonite
gems for sale:
We
have not photographed our Hardystonite gems yet. Please
check back soon.
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