Formula: CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH)
Cyclosilicate (ring silicate), borosilicate, tourmaline group, forms a series with feruvite and with fluor-uvite (Mindat), only limited solid solution with liddicoatite, but complete solid solution series with dravite (Lapis 3.11,23)
Crystal System: Trigonal
Specific gravity: 2.96 to 3.06 measured, 3.115 calculated
Hardness: 7½
Streak: Light brown
Colour: Yellowish brown, brown, blackish brown, bluish black, grey

Metamorphic environments

Uvite occurs typically in calcium-rich rocks subjected to contact metamorphism and metasomatic processes which add boron (HOM); it is frequently found in marble associated with diopside, tremolite, phlogopite or meonite, sometimes with quartz (Dana, Lapis 3.23). Other associates include calcite, dolomite and apatite (HOM).


The official IMA name for this mineral species was uvite; the approval, however, was withdrawn by IMA in 2018 since analysis showed that the type material may be a potentially new oxy-tourmaline. Uvite was finally approved in 2019 with a new type locality. Most specimens historically designated as uvite are actually, as analyses have shown, fluor-uvite, which is much more common than uvite (Mindat). With the exception of specimens from the Facciatoia quarry, uvite from other localities listed below are better described as members of the fluor-uvite/uvite series.

At the type locality, the Facciatoia quarry, San Piero in Campo, Campo nell'Elba, Livorno Province, Tuscany, Italy, uvite occurs at the centre of a 2 to 3 cm wide vein composed of aggregates of dark brown to black tourmaline, penetrating (magnesite + dolomite)-rich hydrothermally altered metaserpentinite. Crystals are euhedral and up to 1 cm in size, brown with a vitreous lustre, conchoidal fracture and grey streak.
Uvite from Facciatoia formed by the reaction between boron-rich fluids, released during the crystallisation process of lithium - cesium - tantalum (LCT) pegmatites, and the surrounding metaserpentinites, altered by contact metamorphism in the aureole of a monzogranitic pluton (MM 86.5.767-776).

At Newcomb, Essex county, New York, USA, uvite occurs as short prismatic crystals to 10 cm or as angular anhedral fragments embedded in albite. In some specimens it has a rim of rossmanite and/or olenite.
The following model for this mineral association is suggested:
(1) Grenville-age metamorphism: uvite, diopside, scapolite, graphite and phlogopite
(2) fracturing followed by invasion of aluminum- and silica-rich fluids that reacted with uvite to form rossmanite and/or olenite; the fluids became Na-rich toward the end of this stage and deposited albite and quartz.
(3) low-temperature alteration of diopside and scapolite to form tremolite (R&M 84.4.366).

Amity, Town of Warwick, Orange county, New York, USA, is an area of granite intrusions into marble and associated gneiss. The marble is mostly composed of white crystalline calcite that often has small flakes or spheres of graphite and phlogopite. Uvite/fluor-uvite occurs in marble as brown crystals to 5 cm. It is often fluorescent a creamy yellow colour (R&M 96.5.441).

At the Yellow Lake south roadcut, St. Lawrence County, New York, USA, uvite occurs as small crystals and crystal fragments embedded in or on quartz. It also occurs with graphite in the surrounding marble (R&M 86.4.356).

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