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General
Kornerupine Information
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Chemical
Formula:
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(Mg,Fe++)4(Al,Fe+++)6(SiO4,BO4)5(O,OH)2
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Composition:
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Molecular
Weight = 649.39 gm
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Magnesium 13.10 % Mg 21.72 % MgO
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Aluminum 23.68 % Al 44.75 % Al2O3
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Iron 1.72 % Fe 2.21 % FeO
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Silicon 16.00 % Si 34.23 % SiO2
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Boron 0.50 % B 1.61 % B2O3
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Hydrogen 0.16 % H 1.39 % H2O
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Oxygen 44.84 % O
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______ ______
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100.00 % 105.91 % = TOTAL OXIDE
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Empirical
Formula:
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Mg3.5Fe2+0.2Al5.7(SiO4)3.7(BO4)0.3O1.2(OH)
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Environment:
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Metamorphic
and alluvial rocks.
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IMA
Status:
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Valid
Species (Pre-IMA) 1884
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Locality:
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Fiskernaes,
SW Greenland. Madagascar
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Name
Origin:
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Named
after the Danish geologist, A. N. Kornerup (1857-1881).
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Synonym:
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ICSD
68636
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PDF
29-852
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Prismatine
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Kornerupine
(22 grms.)
Comments:
Greenish
blue crystal prism of kornerupine.
Location: Madagascar.
©
Image by A. Darbellay
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Kornerupine
Crystallography
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Axial
Ratios:
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a:b:c
=1.1669:1:0.4885
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Cell
Dimensions:
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a
= 16.041, b = 13.746, c = 6.715, Z = 4; V = 1,480.65 Den(Calc)= 2.91
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Crystal
System:
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Orthorhombic
- DipyramidalH-M
Symbol (2/m 2/m 2/m) Space Group: C mcm
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X Ray
Diffraction:
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By
Intensity(I/Io): 2.62(1), 3.008(1), 2.104(0.6),
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Physical
Properties of Kornerupine
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Cleavage:
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[110]
Indistinct
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Color:
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Brown,
Colorless, Green, Greenish yellow, Yellow.
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Density:
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3.3
- 3.34, Average = 3.32
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Diaphaniety:
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Translucent
to opaque
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Fracture:
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Brittle
- Uneven - Very brittle fracture producing uneven fragments.
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Habit:
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Massive
- Fibrous - Distinctly fibrous fine-grained forms.
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Habit:
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Prismatic
- Crystals Shaped like Slender Prisms (e.g. tourmaline).
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Hardness:
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7 -
Quartz
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Luminescence:
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Non-fluorescent.
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Luster:
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Vitreous
(Glassy)
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Streak:
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white
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