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Cavansite
Current inventory:  2 gems
 

Cavansite

  
Cavansite is named for the Calcium, Vanadium, and Silicon in its composition.

Discovered in 1967;   IMA status:  Valid (IMA approved 1973)

 

Chemistry

 

 

Chemical Formula:

CaV5+Si4O114(H2O)

 

Hydrated Calcium Vanadium Silicate

Molecular Weight:

451.42 gm

Composition:

Calcium

8.88 %

Ca

12.42 %

CaO

 

Vanadium

11.28 %

V

20.15 %

V2O5

 

Silicon

24.89 %

Si

53.24 %

SiO2

 

Hydrogen

1.79 %

H

15.96 %

H2O

 

Oxygen

53.16 %

O

 

 

 

 

100.00 %

 

101.77 %

= TOTAL OXIDE

 

 

Classification

   

   

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/H.36-10

Nickel-Strunz 10th Ed. ID:

9.EA.50

 

9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings

Related to:

Dimorphous with Pentagonite. Ishida et al. (2009) suggest that Cavansite is a low-temperature form and Pentagonite a high-temperature from.

Varieties:

None

Synonyms:

None

 

 

Crystal Data

   

   

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

As prismatic crystals, to 1 mm, elongated || [001]; dominant forms {110} and {101}; as spherulitic rosettes, to 5 mm.

Twinning:

None

 

 

Physical Properties

   

 

Cleavage:

Good on {010}

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

3.0 - 4.0

Density:

2.21 - 2.31 (g/cm3)

Luminescence:

None

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

Color:

Brilliant Sky Blue, Dark Blue, Greenish Blue

Transparency:

Subtransparent to Transparent

Luster:

Vitreous

Refractive Index:

1.542 - 1.551  Biaxial ( + )

Birefringence:

0.009

Dispersion:

Weak to Extreme; r < v

Pleochroism:

Pronounced; X = colorless; Y = blue; Z = colorless

 

 

Occurances

   

   

Geological Setting:

In a brown tuff partly filling a fault fissure (Lake Owyhee State Park, Oregon, USA); in a vesicular basalt and red tuff breccia, as cavity fillings and in calcite veinlets (Chapman quarry, Oregon, USA); in pores of altered basalt breccia and tuffaceous andesite (Poona district, India).

Common Associations:

Pentagonite, Calcite, Heulandite, Stilbite, Analcime, Apophyllite, Thomsonite, Copper (Oregon, USA); Stilbite, Calcite, Heulandite, Mordenite, Chalcocite (India).

Common Impurities:

None

Type Locality:

Owyhee Dam, Lake Owyhee State Park, Malheur Co., Oregon, USA

Year Discovered:

1967 (IMA approved 1973)

View mineral photos:

Cavansite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Cavansite is a rare mineral with crystals that are always far too small for faceting and are usually too small even for cabochons. It is mostly collected as mineral specimens for its beautiful blue color displays of radial crystals and
spherulitic rosettes.

Cavansite was originally discovered near Owyhee Dam, Lake Owyhee State Park, Malheur County, Oregon, USA and later at the Chapman quarry, Columbia County, Oregon, USA. Cavansite has recently found as remarkable specimens from quarries around Wagholi, Poona district, Maharashtra, India.
 

  
Cavansite gems for sale:

Cavansite-001

Gem:

Cavansite

Stock #:

CAVANSI-001

Weight:

1.6825 ct

Size:

9.51 x 7.20 x 3.98 mm

Shape:

Oval Cabochon

Color:

Bright Sky Blue w/ chatoyance

Clarity:

Opaque

Origin:

Wagholi, Maharashtra, India

Treatment:

None (natural)

Price:

$48.00    [ Make an offer ]

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Cavansite-001

A rare gem from Wagholi, Poona district, Maharashtra, India with brilliant color and slight chatoyance. It is very rare to find a Cavansite gem with chatoyance.

 

Cavansite-002

Gem:

Cavansite

Stock #:

CAVANSI-002

Weight:

3.5340 ct

Size:

11.51 x 8.91 x 5.58 mm

Shape:

Oval Cabochon

Color:

Deep Sky Blue

Clarity:

Opaque

Origin:

Wagholi, Maharashtra, India

Treatment:

None (natural)

Price:

$48.00  (RESERVED)

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Cavansite-002

A rare gem from Wagholi, Poona district, Maharashtra, India with an intense deep sky blue color.

 

 


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