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Formula: Ca5(AsO4)3Cl
Anhydrous arsenate,
apatite group,
apatite supergroup
Crystal System: Hexagonal
Specific gravity: 3.60 measured, 3.63 calculated
Hardness: 5
Streak: White
Colour: Colourless to greyish white
Luminescence: Fluoresces bright orange under short wave UV, not discernibly fluorescent under long wave UV.
Phosphorescence is weakly discernible in massive material from Franklin, but was not observed on crystals from the
other localities.
Environments
Turneaureite is a rare component of manganiferous ores in
high-grade marbles, possibly confined to the
amphibolite and
granulite facies
(CM 23.2.251-254)
Localities
There are three co-type localities, the Långban Mine, Långban Ore District, Filipstad, Värmland County, Sweden, the
Franklin Mine, Franklin, Sussex County, New Jersey, USA, and the Empire State No. 4 Mine, Balmat, Fowler, St.
Lawrence County, New York, USA.
At the Långban Mine, Långban Ore District, Filipstad, Värmland County, Sweden, turneaureite occurs rarely as
euhedral crystals associated with calcite and several generations of
secondary andradite,
on massive andradite-magnetite
ore.
In all three co-type localities turneaureite ocurs in high-grade
marble terranes.
At Långban, manganiferous ores were metamorphosed to the
amphibolite grade of
regional metamorphism
(CM 23.2.251-254).
Turneaureite from Långban - Image
At the Franklin Mine, Franklin, Sussex County, New Jersey, USA, At Franklin, turneaureite occurs in large,
massive samples up to 5 x 3 x2 cm in size. It is greyish white, does not occur in euhedral crystals, and has a duller
lustre than the Swedish material. It is associated with magnetite,
andradite and manganoan
calcite, all of which occur in centimetre-size crystals or aggregates.
In all three co-type localities turneaureite ocurs in high-grade
marble terranes.
The Franklin ores and the enclosing Franklin Marble were metamorphosed to the
amphibolite to
granulite facies
(CM 23.2.251-254).
Turneaureite from the Franklin Mine -
Image
At the Empire State No. 4 Mine, Balmat, Fowler, St. Lawrence County, New York, USA, turneaureite occurs in the
manganese-rich siliceous
marbles exposed on the 2500 level.
Manganese-rich pods are scattered within several of the siliceous
marble units. The turneaureite forms subhedral, isolated
crystals intimately associated with donpeacorite, a
manganese-rich amphibole
("tirodite"), minor ferrian braunite,
dravite, anhydrite and
manganese-bearing dolomite.
In all three co-type localities turneaureite ocurs in high-grade
marble terranes. Peak metamorphic conditions in the Balmat area were
6.5 +/- 1.0 kbar and 650 +/- 30oC.
(CM 23.2.251-254)
Turneaureite specimens are massive aggregates of brownish crystals with spectacular bright orange
fluorescence under short wave UV
(MinRec 56.1.62).
Turneaureite from the Empire State No. 4 Mine
- Image
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