Images
Formula: CaTiO3
Valence: CaTi4+O3
Simple oxide, perovskite subgroup,
stoichiometric perovskites group,
perovskite supergroup,
titanium-bearing mineral
Dysanalyte is a niobium-bearing variety of perovskite
Crystal System: Orthorhombic
Specific gravity: 3.98 to 4.26 measured, 4.02 calculated for synthetic material
Hardness: 5½
Streak: Colourless, greyish white
Colour: Dark brown, black, red-brown, yellow shades
Solubility: Insoluble in hydrochloric and nitric acids; slightly soluble in sulphuric acid
Common impurities: Fe,Nb,Ce,La,TR
Environments:
Plutonic igneous environments
Carbonatites
Metamorphic environments
Earth's lower mantle
Perovskite is an accessory mineral in silica-poor rocks, such as
nepheline syenite,
kimberlite (common) and carbonatite. It also occurs in
calcareous skarn. It is common in
chlorite,
talc or serpentine rocks
(Webmin, HOM). Associated minerals include åkermanite –
gehlenite, nepheline,
titanite, ilmenite and
magnetite
(HOM).
It is also a mineral of Earth's lower mantle
(Wiki).
Localities
At the Oka Rare Metals mine, Saint-Joseph-du-Lac, Deux-Montagnes RCM, Laurentides, Québec, Canada, the
niobium minerals, represented chiefly by
pyrochlore, but also including niobian perovskite (dysanalyte) and
niocalite, are disseminated irregularly throughout the complex of carbonate and
alkaline rocks.
All of the niobian perovskite described here was concentrated, from one mill sample taken from surface trenches, and
other samples from diamond drill core assay rejects. The samples are all relatively fine-grained, and consist predominantly of
white calcite with varying amounts of diopside,
biotite and apatite. Accessory minerals include
pyrochlore, niobian perovskite,
magnetite, pyrrhotite,
dolomite, nepheline and
monticellite, as well as others occurring in extremely small quantities. The
niobian perovskite occurs primarily as small, black, cubic crystals, generally less than 0.2 mm to a side. Most of the
larger crystals are embayed by, and commonly contain inclusions of, other minerals, usually
calcite. A few crystals were found to be rimmed by extremely fine-grained
pyrochlore, giving the impression that the niobian perovskite has been
partially replaced by, or altered to, pyrochlore. In transmitted light the niobian
perovskite is dark greyish brown. Practically all of the crystals exhibit complex twinning. The specific gravity of the
analysed niobian perovskite is 4.40. This is much higher than the theoretical specific gravity of pure CaTiO3
(which is 4.04), and can probably be attributed to its high niobium content
(CM 7.5.683-697).
Perovskite from the Oka Complex - Image
The type locality is the Akhmatovskaya Kop', Nazyamskie Mountains, Zlatoust, Chelyabinsk Oblast, Russia.
Back to Minerals