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Click on a
letter above to view the list of gems. |
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| Chemistry:
AlO(OH)
| Discovered
in 1801;
IMA
status: Valid (pre-IMA; Grandfathered). The name Diaspore is from the Greek word diaspeirein,
meaning to scatter, because the mineral
falls apart easily under the flame of a blowpipe. |
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Classification
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Mineral
Classification: |
Hydroxides
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Strunz 8th
Ed. ID:
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4/F.06-10 |
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4 : Oxides & Hydroxides F : Hydroxides and oxidic
hydrates, water-bearing oxides with layered structure 06 : Diaspore -
Goethite - Faitknechtite series
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Crystal
Data
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Crystallography:
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Orthorhombic
- Dipyramidal |
Crystal
Habit:
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As crystals,
platy and elongated to acicular, to 40 cm; stalactitic,
foliated, scaly; disseminated, massive. Twinning: to
form heart-shaped twins or pseudohexagonal aggregates.
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Physical
Properties
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Cleavage: |
[010]
Perfect, [110] distinct, [100] in traces
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Fracture: |
Conchoidal
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Tenacity:
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Very
Brittle
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Moh's
Hardness: |
6.5
- 7.0
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Density:
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3.20 - 3.50 (g/cm3) |
Radioactivity:
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Not
Radioactive
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Optical
Properties
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Color: |
White,
pale gray, colorless, greenish gray, brown, pale yellow,
pink, lilac; color may vary with viewing direction in
the same specimen, may show a color change from brownish
green in daylight to raspberry pink in artificial light. |
Transparency: |
Transparent to Translucent |
Luster: |
Adamantine,
Vitreous, Pearly on cleavage faces. |
Refractive
Index: |
1.700 - 1.752 Biaxial
( + ) |
Birefringence: |
0.047 - 0.050 |
Dispersion: |
Weak
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Pleochroism: |
Strong;
may be reddish brown to reddish violet; grayish green
to green.
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Occurances
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Geological
Setting: |
Typically
a final product of diagenesis in bauxite deposits formed
by the tropical weathering of alumino-silicate rocks;
from hydrothermal alteration of aluminous minerals;
a hydrothermal mineral in some alkalic pegmatites. |
Type
Locality: |
Mramorsk (Mramorskoye) Zavod, Kosoi Brod Village,
Ekaterinburg (Yekaterinburg; Sverdlovsk), Sverdlovskaya Oblast', Urals Region,
Russia |
Year
Discovered: |
1801 |
View
mineral photos: |
Diaspore
Mineral Photos and Locations |
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More
Information
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Mindat.org Webmineral.com |
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Diaspore is a very rare gem with gem quality crystals
coming mainly from bauxite deposits at Mamaris, Yatagan,
Mugla Province, Turkey. It is hard enough for use in
jewelry, but too brittle. Some
gems have very strong pleochroism with colors changing
from pale golden-green to mauve-brown. Very rarely,
gems may display colors of violet-blue and dark
red.
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Diaspore
gems for sale:
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Gem:
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Diaspore |
Stock
#:
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DIASP-001 |
Weight:
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9.73
ct |
Size: |
15.07
x 10.66 x 6.80 mm |
Shape: |
Emerald |
Color: |
Color
Change |
Clarity: |
Eye
Clean to MI |
Origin: |
Mugla
Province, Turkey |
Treatment: |
None
(natural) |
Price: |
SOLD
(but we have others) |
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 Mugla Province, Aegean Region, Turkey.
It is a large and beautiful example of the
color change properties exhibited by some
Diaspore gems. As you can see in the pictures,
it turns from slightly greenish yellow (actually
a little more greenish than the picture
shows) in daylight to a reddish violet under
incandescent light. This gem is mostly eye
clean with some veils through the middle
and some cleavage planes visible through
the table.
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