Calzirtite

calzirtite

forsterite

baddeleyite

zirconolite

Images

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

Carbonatites
Placer deposits

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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