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Gemstones 250x250

The Mineral uvite

Dark Green Uvite Cluster

Uvite is an uncommon form of Tourmaline, and it forms different crystal formations than the most of the other Tourmalines. Though it lacks the color diversity as some of the other Tourmaline forms, it does occur in beautiful green and reddish-brown crystals, as well as lustrous submetallic crystals. The name Uvite is derived from the type locality of the Uva Province, in Sri Lanka, where it was first identified.

Uvite is very similar to Dravite Tourmaline, and they sometimes for together in a single crystal. It can sometimes be very difficult to make an exact distinction between Dravite, Uvite, and the newly designated Fluor-uvite.

Chemical Formula

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

Color

Light to dark green, light to dark brown, reddish brown, red, purple, brownish-yellow, white, gray, black. May also be multicolored with light and dark brown streakings.

Crystal System

Hexagonal

Properties

Streak
White
Hardness
7.5
Transparency
Transparent to opaque
Specific Gravity
3.0 - 3.2
Luster
Vitreous, submetallic
Cleavage
3,2
Fracture
Conchoidal to uneven
Tenacity
Brittle
Other ID Marks
May fluoresce yellow in shortwave ultraviolet light.

Crystal Habits

Most often in short and stubby crystals with complete terminations. Prismatic crystals are rare. Also occurs in columnar aggregates, equant crystal masses, radiating, and massive. Crystals are occassionally striated.

3D Crystal Atlas

Additional Information

Composition
Basic calcium magnesium iron aluminum boro-silicate
In Group
Silicates; Cyclosilicates; Tourmaline Group
Striking Features
Colors, crystal forms, and localities.
Environment
In metamorphosed Magnesite deposits, and in metamorphic skarns and marbles.
Rock Type
Metamorphic

Varieties

 -   Form of Uvite where part of the hydroxyl is replaced with fluorine. Fluor-uvite was recognized as a distinct mineral species by the IMA in 2010, with the following chemical formula: Ca(Mg,Fe2+)3Al5Mg(BO3)3Si6O18OH)3F

Uses

Uvite, being an uncommon form of Tourmaline, is mainly a collectors minerals.

Noteworthy Localities

Uvite is not a common mineral. The best locality for this mineral is Serra das Éguas, Brumado, Bahia, Brazil, where it occurs in lustrous gemmy red and green crystals. One of the most famous occurrence in the U.S. is the Bower Powers Farm, Pierrepont, St. Lawrence Co., New York, where lustrous black crystals can be found. Recent analysis of these Pierrepont Tourmalines have determined them as having Fluor-uvite cores and Dravite rims. However, most collectors still refer to them as Uvite from their original designation, and are in no rush to change their mineral labels.

Brownish-red translucent Fluor-uvite comes from the Bush Farm (also known as the Reese Farm), near Richville, St Lawrence Co., New York. Good crystals have come from the marbles at Franklin and Hamburg, Sussex Co., New Jersey; and Amity, Orange Co., New York. In Canada, Uvite comes from the Tait Farm in Dungannon, in the Bancroft District, Ontario, Canada. A new occurrence producing deep emerald-green Uvite has been reported from Mogok, Burma (Myanmar).

Common Mineral Associations

Calcite, Quartz, Magnesite, Dolomite, Tremlolite, Actinolite, Hematite

Distingushing Similar Minerals

Dravite - May be very difficult to distinguish.
Schorl - Usually occurs in different environments, and crystal habits differ.
Garnet - Forms in different crystals.


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