Fundamental Minerals

Sialic Minerals

Feldspars

Feldspathoids

Quartz

Femic Minerals

Spodumene

Accessory Minerals

Rare Accessory

Alteration Products

Microstructures

Rocks

Jacupiranga complex

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 O^2- 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

perovskite(oka).jpg

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

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

Sample kindly given to me by Juarez Fontana

Bibliography

• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Le Maitre, R. W., Streckeisen, A., Zanettin, B., Le Bas, M. J., Bonin, B., Bateman, P., & Lameyre, J. (2002). Igneous rocks. A classification and glossary of terms, 2. Cambridge University Press.
• Middlemost, E. A. (1986). Magmas and magmatic rocks: an introduction to igneous petrology.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.

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