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Albite (variety of Feldspar)
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Discovered in 1815; IMA status: Valid (pre-IMA; Grandfathered)
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Chemistry
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Chemical
Formula: |
Na[AlSi3O8]
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Sodium
Aluminum Silicate |
Molecular
Weight: |
263.02 gm
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Composition: |
Sodium |
8.30 % |
Na |
11.19 % |
Na2O
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Calcium |
0.76 % |
Ca |
1.07 % |
CaO
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Aluminum |
10.77 % |
Al |
20.35 % |
Al2O3
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Silicon |
31.50 % |
Si |
67.39 % |
SiO2
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Oxygen |
48.66 % |
O |
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100.00 % |
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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/J.07-20
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Nickel-Strunz 10th
Ed. ID:
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9.FA.35
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9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic
H2O
A : Tektosilicates without additional non-tetrahedral anions
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Related
to: |
Feldspar
Group. Plagioclase Series. Na-rich end member of the Albite - Anorthite
Series. Anorthoclase - Anorthite - Banalcite Series.
Low-
and high-temperature structural modifications are recognized.
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Members
of Group: |
Feldspar
Group:
Albite,
Amazonite, Andesine, Anorthite, Anorthoclase, Banalsite,
Buddingtonite, Bytownite, Celsian, Dmisteinbergite,
Hyalophane, Labradorite, Microcline, Oligoclase, Orthoclase,
Paracelsian, Reedmergnerite, Sanidine, Slawsonite, Stronalsite,
Svyatoslavite
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Varieties: |
Albite
Moonstone, Andesine, Cleavelandite, High Albite, Lazur-Feldspath,
Low Albite, Oligoclase, Oligoclase-Albite, Pericline,
Peristerite
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Synonyms: |
Acid
Plagioclase, Analbite (of Alling), Cryptoclase, Cryptose,
Hyposclerite, Kieselspath, Natro-Feldspat, Olafite,
Sodaclase, Soda Feldspar, Tetartine, White Feldspar,
White Schorl, Zygadite
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Crystal
Data
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Crystallography:
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Triclinic - Pinacoidal
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Crystal
Habit:
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Crystals
commonly tabular || {010}, may be curved, to 3 cm; divergent
aggregates, granular, cleavable, massive.
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Twinning:
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Common
around [010] or {010}, giving polysynthetic striae on
{001} or {010}; many other laws, contact, simple and
multiple.
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Physical
Properties
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Cleavage: |
[001]
Perfect, [010] Very Good, {110} Imperfect
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Fracture: |
Irregular/Uneven,
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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2.6
- 2.65 (g/cm3)
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Luminescence:
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Fluorescent;
cherry red under SW UV, white under LW UV |
Radioactivity:
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Not
Radioactive
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Optical
Properties
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Color: |
Colorless,
white to gray, bluish, greenish, reddish; may be chatoyant
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Transparency: |
Transparent
to translucent |
Luster: |
Vitreous;
pearly on cleavages |
Refractive
Index: |
1.528
- 1.542
Biaxial ( + ) (low); Biaxial ( - ) (high)
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Birefringence: |
0.0090
- 0.0100
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Dispersion: |
Weak; r < v
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Pleochroism: |
None
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Occurances
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Geological
Setting: |
A
major constituent of granites and granite pegmatites,
alkalic diorites, basalts, and in hydrothermal and alpine
veins. A product of potassium metasomatism and in low-temperature
and low-pressure metamorphic facies and in some schists.
Detrital and authigenic in sedimentary rocks. |
Common
Associations: |
Biotite,
Hornblende, Orthoclase, Muscovite, Quartz |
Common
Impurities: |
Ca,
K, Mg |
Type
Locality: |
Finnbo (Finbo), Falun, Dalarna, Sweden
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Year
Discovered: |
1815
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View
mineral photos: |
Albite
Mineral Photos and Locations |
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More
Information
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Mindat.org
Webmineral.com
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Albite
is
a rare member of the Plagioclase Feldspars of the Feldspar Group of minerals that includes Albite,
Amazonite,
Andesine, Anorthite, Bytownite, Hyalophane, Labradorite,
Moonstone,
Oligoclase, Orthoclase, Sanidine
and Sunstone. The
Plagioclase Feldspars form a series between Albite and
Anorthite. Albite is the sodium-rich end member while
Anorthite is the calcium-rich end member and Oligoclase is the
intermediate member. Albite is also an
end member of the alkali or K-Feldspars. A variety
of Albite called Cleavelandite
is rarely found as white inclusions in Quartz.
Albite is considered a fluorescent mineral because it
fluoresces
cherry red under SW UV light and white under LW UV light.
Albite
was named in 1815 by Johan Gottlieb Gahn and Jöns Jacob Berzelius from the
Latin word albus, meaning white, in allusion
to its typical color. Albus is also the root for
the word albino.
Sources
of Albite are: Minas Gerais, Southeast Region, Brazil;
Bancroft District, Hastings County, Ontario, Canada;
Wicklow Township, Hastings County, Ontario, Canada;
Poudrette quarry, Mont Saint-Hilaire, Rouville County, Québec, Canada;
Skardu Road, Skardu District, Baltistan, Northern Areas,
Pakistan; Hawk Mine, Hawk-Bakersville, Spruce Pine District,
Mitchell County, North Carolina, USA.
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Albite
gems for sale:
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yet. Please
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