Perovskite - CaTiO3

Perovskite was discovered in the Ural Mountains of Russia by Gustav Rose in 1839 and is named after Russian mineralogist Lev Perovski (1792–1856). The idealized structure of perovskite is essentially a cubic-close-packed configuration of Ca2+ and O2- ions with Ti4+ in some octahedral sites between close-packed layers. Common Perovskite is essentially CaTiO3, however, numerous single and couple substitutions are possible, and varieties rich in Cerium (knopite), Niobium (dysanalyte) and Niumbium and REE (loparite) have been described.
These varieties tend to be alkali-rich through coupled substitutions od Na+ and Ce5+ or Nb5+ for Ca2+ and Ti4+. Numerous other elements may be present in significant amounts, including Th, La, U, Fe, Zr and Al.

Perovskite is most common as tiny accessory crystals of either magmatic or deuteric origin in silica-deficient igneous rocks. In highly alkaline rocks (nephelin-syenites or ijolites), perovskite forms in association with nepheline or melilite. Tiny crystals of perovskite are common in peridotites, olivinites, pyroxenites and in basic pegmatites and carbonatites. Metamorphism of impure Limestone, especially in contact with alkaline intrusions, may yield Perovskite crystals in contact marble.

Optical Properties:

Relief: Very High
Form: Most frequently as tiny crystals of either cubic or octahedral habit
Color: Perovskite may be colorless, pale yellow ore pale red, but commonly is dark red-brown
Interference colors: Isotropic

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Sharp black cubes of perovskite, associated with akermanite (white). Oka complex, Quebec, Canada.



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Black lustrous cube of perovskite. St Lawrence Columbium mine, Oka complex, Quebec, Canada.



Sample kindly given to me by Juarez Fontana

Bibliography



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.


Photo
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Brown Perovskite crystals and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
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Isotropic Perovskite crystals and pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. XPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
perovskite(46).jpg

Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
perovskite(49).jpg

Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
perovskite(51).jpg

Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
perovskite(52).jpg

Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
perovskite(53).jpg

Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
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Isotropic Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. XPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
perovskite(56).jpg

Brown Perovskite crystals, red phlogopite and pale-green pyroxene in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 2x (Field of view = 7mm)
perovskite(57).jpg

Isotropic Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. XPL image, 2x (Field of view = 7mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)
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Brown Perovskite crystals in a Pyroxenite. Tapira phosphate mine, Brazile. PPL image, 10x (Field of view = 2mm)