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Cleavelandite  (a variety of Albite) (inclusions in Quartz)
Current inventory:  0 gems
 

  
Cleavelandite is named after Parker Cleaveland, a professor of geology and mineralogy at Bowdoin College in Maine during the early 1800s.

Discovered in 1815 (Albite).   IMA status: Not Valid (Cleavelandite is a variety of Albite)

Chemistry

Chemical Formula:

Na[AlSi₃O₈]

Sodium Aluminum Silicate

Molecular Weight:

263.02 gm

Composition:

Soldium

8.30 %

Na

11.19 %

Na₂O

Calcium

0.76 %

Ca

1.07 %

CaO

Aluminum

10.77 %

Al

20.35 %

Al₂O₃

Silicon

31.50 %

Si

67.39 %

SiO₂

Oxygen

48.66 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/J.07-20

Nickel-Strunz 10th Ed. ID:

9.FA.35

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H₂O
A : Tektosilicates without additional non-tetrahedral anions

Related to:

Variety of Albite. Feldspar Group. Plagioclase Series. Na-rich end member of the Albite-Anorthite Series. Low- and high-temperature structural modifications exist. Low- and high-temperature structural modifications are recognized.

Synonyms:

Clevelandite

Crystal Data

Crystallography:

Triclinic - Pinacoidal

Crystal Habit:

(Albite) Crystals commonly tabular || {010}, may be curved, to 3 cm; divergent aggregates, granular, cleavable massive.

Twinning:

(Albite) Common around [010] or {010}, giving polysynthetic striae on {001} or {010}; many other laws, contact, simple and multiple.

Physical Properties

Cleavage:

Perfect on {001}, very good on {010}, imperfect on {110}

Fracture:

Irregular/Uneven to Conchoidal

Tenacity:

Brittle

Moh's Hardness:

6.0 - 6.5

Density:

2.60 - 2.65 (g/cm³)

Luminescence:

Fluorescent, Short UV=cherry-red blue, Long UV=white.

Radioactivity:

Not Radioactive

Other:

F

Optical Properties

Color:

White to Gray, Bluish, Greenish, Reddish; may be chatoyant.

Transparency:

Transparent to Translucent

Luster:

Vitreous, Pearly on cleavages

Refractive Index:

1.528 - 1.542  Biaxial ( + ), Biaxial ( - ) for high variety

Birefringence:

0.0090 - 0.0100

Dispersion:

Weak; r < v

Pleochroism:

None

Occurances

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:

Quartz, Orthoclase, Muscovite, Biotite, "Hornblende"

Common Impurities:

Ca, K, Mg

Type Locality:

(Albite) Finnbo (Finbo), Falun, Dalarna, Sweden

Year Discovered:

(Albite) 1815

View mineral photos:

Cleavelandite Mineral Photos and Locations

More Information

Mindat.org  (Cleavelandite)
Mindat.org  (Albite)
Webmineral.com  (Albite)

Cleavelandite is a platy variety of Albite which is a member of the Feldspar Group of minerals that includes Albite, Amazonite, Andesine, Anorthite, Bytownite, Hyalophane, Labradorite, Moonstone, Oligoclase, Orthoclase, Sanidine and Sunstone. Cleavelandite is not a gemmy variety but forms a very attractive inclusion in Quartz. Round, white "snow ball" Cleavelandite inclusions in faceted Quartz are very collectable. Although Albite is widespread, Cleavelandite inclusions in Quartz are relatively rare. The best source seems to be Minas Gerais, Brazil.
 

  
Cleavelandite gems for sale:

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