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Formula: Ca2Zr5Ti2O16
Oxide, calzirtite group,
zirconium- and titanium-
bearing mineral
Crystal System: Tetragonal
Specific gravity: 4.90 to 5.01 measured, 5.15 calculated
Hardness: 6 to 7
Streak: Brown
Colour: Dark brown, nearly black
Luminescence: Does not fluoresce under UV, wavy red cathodoluminescence
Solubility: Partly soluble when heated in concentrated sulphuric, phosphoric or hydrochloric acid
Environments
Calzirtite is a characteristic accessory mineral in alkalic and ultramafic complexes associated with
carbonatites; it is typically found in residual soils and
alluvium. Associated minerals include forsterite,
pyroxene, calcite,
magnetite, phlogopite,
niobium-bearing perovskite,
apatite, rutile,
anatase, baddeleyite and
zirconolite
(HOM).
Localities
The type locality is the Gornoozerskii carbonatite complex, Sakha, RussiaKugda massif, Maimecha and Kotui Rivers
Basin, Krasnoyarsk Krai, Russia. In the Guly massif calzirtite was observed in
calcitic and dolomite
calcitic
carbonatites. It exists here in extremely small quantities
and is associated with phlogopite, rarely with
diopside-augite, with
forsterite, baddeleyite and
anatase, and sometimes forms intergrowths with
dysanalyte and apatite. In
considerably larger quantities, calzirtite was observed in the same associations in the alluvial placers of
carbonatites in the Bezimyani and Zayachi streams. In the
Kugda, Magan, and Odikhinch massifs, calzirtite was found in placers of the streams that erode
carbonatites and alkaline rocks. Here the minerals
associated with calzirtite include olivine,
apatite, perovskite,
pyrochlore and diopside
(AM 52.1880-1884).
Calzirtite forms tabular concretions 3 x 4 x 1 mm3 in size, composed of complex trillings. Single
crystals are tetragonal, prismatic and bipyramidal. The colour is dark brown, nearly black, and the lustre is
semi-metallic to adamantine. It has strong, reddish brown internal reflections
(AM 46.1515)
Calzirtite from the Gornoozerskii Carbonatite
Complex - Image
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