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Formula: Pb6(Te4+O3)5(S6+O3S2–)
Thiosulphate, tellurium-bearing mineral
Crystal System: Hexagonal
Specific gravity: 6.888 calculated for the empirical formula and 6.977 calculated for the ideal formula
Hardness: 2
Streak: White
Colour: Beige
Luminescence: Nonfluorescent under long and short wave ultraviolet light
Solubility: Slowly soluble in concentrated hydrochloric acid at room temperature
Environments
Metamorphic environments
Hydrothermal environments
Localities
At the Delamar mine, Delamar Mining District, Lincoln County, Nevada, USA,
matthiasweilite occurs as a
secondary mineral, associated with
adanite, choloalite,
northstarite and other oxysalts in a quartz-rich matrix, that
developed in an altered primary ore along with
altaite,
tetrahedrite-(Zn),
native gold and other sulphides and
selenides
(CM 60.5.805–814).
At the type locality, the North Star Mine, Mammoth, Tintic Mining District, Juab County, Utah, USA, the mine
exploited a polymetallic
gold-silver-copper-lead
vein deposit emplaced in contact-metamorphosed dolomite, and it was the
largest producer of gold in the Tintic district. The principal ore minerals were
galena, cerussite and
enargite, and the prominent gangue
minerals were quartz and baryte.
The northstarite is an oxidation-zone mineral known from only one small specimen. It occurs as short prisms
with pyramidal terminations, up to about 1 mm in length, in a vug in massive
quartz-baryte-enargite-pyrite. Other
secondary minerals found in association with northstarite
are adanite, anglesite,
azurite, chrysocolla,
fluorapatite,
plumbogummite, tellurite,
zincospiroffite, and an unidentified poorly crystalline
copper-tellurite
(CM 58.4.533-542).
Northstarite from the Upper Dumps -
Image
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