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Formula: CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3F
Cyclosilicate (ring silicate), borosilicate,
tourmaline group, forms series with
uvite and with fluor-dravite
Crystal System: Trigonal
Specific gravity: 2.97 to 3.14 measured, 3.08 calculated
Hardness: 7½
Streak: Light-brown, light-green, or white
Colour: Black, greenish-black, brownish-black, brown, green, colourless
Luminescence: May show a weak mustard-yellow fluorescence under short wave UV
Electrical: Piezoelectric, pyroelectric
Common impurities: Mn,Ti,Na,Cr,V,Zn,H2O
Environments
Fluor-uvite is found in calcium-rich rocks subjected to contact
metamorphism and the addition of boron. Associated minerals include apatite,
calcite, dolomite,
scapolite and tremolite
(Mindat).
Localities
There are four co-type localities, Franklin, the Fowler quarry, the Franklin quarry and the Franklin mine, all in the Franklin
Mining District, Sussex county, New Jersey, USA.
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 Gouverneur, St Lawrence county, New York, USA, fluor-uvite is relatively common and is the
predominant tourmaline at the Bush farm. Crystals of fluor-uvite up
to 14 cm have
been found here
(R&M 91-6.523-525).
At the The Selleck Road Tremolite and Tourmaline Locality, West Pierrepont, St. Lawrence County, New York, USA,
fluor-uvite
occurs as both single crystals and matrix specimens, up to 16 cm in size. Associated minerals include
tremolite, calcite and
phlogopite
(R&M 91-2.116-131).
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