Uvite (variety of Tourmaline)
Current inventory:  0 gems
 

  
Uvite is named for the Type Locality area, Uva Province, Sri Lanka.

Discovered in 1929; IMA status: Valid (IMA redefined, approved 2010)

Chemistry

Chemical Formula:

(Ca,Na)(Mg,Fe²⁺)₃Al₅Mg(BO₃)₃Si₆O₁₈(OH,F)₄

Calcium Sodium Magnesium Iron Aluminum Boro-Silicate Hydroxide Fluoride

Molecular Weight:

970.23 gm

Composition:

Sodium

0.59 %

Na

0.80 %

Na₂O

Calcium

3.10 %

Ca

4.33 %

CaO

Magnesium

5.64 %

Mg

9.35 %

MgO

Aluminum

13.90 %

Al

26.27 %

Al₂O₃

Iron

4.32 %

Fe

5.55 %

FeO

Silicon

17.37 %

Si

37.16 %

SiO₂

Boron

3.34 %

B

10.76 %

B₂O₃

Hydrogen

0.31 %

H

2.79 %

H₂O

Oxygen

49.47 %

O

Fluorine

1.96 %

F

1.96 %

F

- %

F

100.00 %

98.14 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/E.19-90

Nickel-Strunz 10th Ed. ID:

9.CK.05

9 : SILICATES (Germanates)
C : Cyclosilicates
K : [Si₆O₁₈]₁₂- 6-membered single rings, with insular complex anions

Related to:

Tourmaline Group. Dravite - Uvite Series. The Mg-analogue of Feruvite.

Members of Group:

Tourmaline Group: Buergerite, Chromdravite, Dravite, Elbaite, Feruvite, Fluor-Dravite, Fluor-Schorl, Foitite, IMA2009-088, Liddicoatite, Luinaite-(OH), Magnesiofoitite, Olenite, Oxy-Dravite, Oxy-Rossmanite, Oxy-Schorl, Povondraite, Rossmanite, Schorl, Uvite, Vanadiumdravite.

Varieties:

None

Synonyms:

IMA2000-030a

Crystal Data

Crystallography:

Trigonal - Ditrigonal Pyramidal

Crystal Habit:

Crystals prismatic to equant, may be tabular, pyramidal, in radiating groups, to 15 cm. Cross sections are typically triangular with curved, convex sides.

Twinning:

None

Physical Properties

Cleavage:

Indistinct on {1011}

Fracture:

Irregular/Uneven, Conchoidal

Tenacity:

Brittle

Moh's Hardness:

7.5

Density:

2.97 - 3.14 (g/cm³)

Luminescence:

May fluoresce a weak mustard-yellow under SW UV.

Radioactivity:

Not Radioactive

Other:

Piezoelectric and Pyroelectric

Optical Properties

Color:

Light to dark green, yellowish brown, red, brown, blackish brown, black, colorless; may be zoned parallel to prism faces.

Transparency:

Semi-Transparent, Translucent, Opaque

Luster:

Vitreous, Resinous, Greasy

Refractive Index:

1.637 - 1.668  Uniaxial ( - )

Birefringence:

0.0180 - 0.0290

Dispersion:

n/a

Pleochroism:

Weak; O = pale yellow; E = colorless

Occurances

Geological Setting:

Typically in calcium-rich rocks subjected to contact metamorphism and metasomatic processes which added boron.

Common Associations:

Calcite, Dolomite, Tremolite, Apatite, Scapolite

Common Impurities:

Mn, Ti, Na, Cr, V, Zn, H₂O

Type Locality:

Uva Province, Sri Lanka

Year Discovered:

1929

View mineral photos:

Uvite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Uvite is a rare member of the Tourmaline Group of minerals that includes Achroite, Dravite, Liddicoatite, Povondraite, Rubellite, Schorl and Uvite. Uvite is a magnesium/iron rich member of the Tourmaline Group. Uvite was once considered to be a very rare variety of the Tourmaline Group but has recently become more readily available on the gem and mineral markets. Other more common and more well know Tourmalines are Elbaite (various colors and colorless, lithium rich), Schorl (opaque black, iron rich), Dravite and Liddicoatite. Most colored Tourmaline used as gemstones are Elbaite Tourmaline. Uvite is named for the Type Locality area, Uva Province, Sri Lanka and is available in colors of light to dark green, yellowish brown, red, brown, blackish brown, black, colorless and may be zoned parallel to prism faces.

Distribution: In Uva Province, Sri Lanka. From the Sagaing district, Myanmar (Burma). In the USA, from Franklin and Hamburg, Sussex County, New Jersey; in New York, at Gouverneur, Pierrepont, Dekalb and elsewhere in St. Lawrence County, and at Horicon, Warren County; and from East Hampton, Middlesex County, Connecticut. From Brumado, Bahia, Brazil. At Hnústa, Slovakia.
 

  
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