Clinopyroxene - XYZ2O6

Optical properties:

• Colour and Pleochroism: Usually colourless, gray, pale green or pale brown, darker colours associated with Fe-rich varieties titanaugite is more distinctly coloured from brown/pink to violet.
• Form: Form stubby prisms elongate along the c-axis, basal sections are 4 or 8 sided and show two cleavages at 90.°
• Cleavage: Parallel to {110}, which intersect at 90°.
• Twinning: Simple and lamellar twins and composition planes, which in combination may form a herringbone pattern.
• Alteration: Commonly alter to uralite (a light coloured amphibole), or may alter to serpentine, chlorite, biotite, carbonates and /or other silicates.
• Relief: High positive.
• Distinguishing Features: Inclined extinction, higher birefringence, 2nd order interference colours, low 2V, optically positive in comparison with opx.

For structural characteristics and for the classification of the Pyroxene group of minerals see the page structural characteristics and classification

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
xenolitepirosseniticovulsini(22).jpg

Pyroxene in basal section (with colorless apatite inclusions) in a xenolith from Vulsini volcano, Italy. PPL image, 2x (Field of view = 7mm)
pyroxene2020(33).jpg

Pyroxene in basal section (with colorless apatite inclusions) in a xenolith from Vulsini volcano, Italy. PPL image, 10x (Field of view = 2mm)
pyroxene2020(34).jpg

Pyroxene in basal section (with colorless apatite inclusions) in a xenolith from Vulsini volcano, Italy. PPL image, 10x (Field of view = 2mm)
pyroxene2020(1).jpg

Aegirine (grass-green) crystals in a alkaline syenite from Murun massif, Siberia, Russia. PPL image, 2x (Field of view = 7mm)
pyroxene2020(2).jpg

Aegirine (green) crystals in a alkaline syenite from Murun massif, Siberia, Russia. XPL image, 2x (Field of view = 7mm)
pyroxene2020(3).jpg

Aegirine (grass-green) crystals in a alkaline syenite from Murun massif, Siberia, Russia. PPL image, 2x (Field of view = 7mm)
pyroxene2020(4).jpg

Aegirine (grass-green) crystals in a alkaline syenite from Murun massif, Siberia, Russia. PPL image, 2x (Field of view = 7mm)
pyroxene2020(5).jpg

Aegirine (grass-green) crystals in a alkaline syenite from Murun massif, Siberia, Russia. PPL image, 2x (Field of view = 7mm)
pyroxene2020(17).jpg

Aegirine (grass-green) crystals in a alkaline syenite from Mnt. Flora, Lovozero massif, Kola, Russia. PPL image, 10x (Field of view = 2mm)
pyroxene2020(18).jpg

Aegirine (grass-green) crystals in a alkaline syenite from Mnt. Flora, Lovozero massif, Kola, Russia. XPL image, 10x (Field of view = 2mm)
pyroxene2020(19).jpg

Aegirine crystal (zoned basal section) in a alkaline syenite from Mnt. Flora, Lovozero massif, Kola, Russia. PPL image, 10x (Field of view = 2mm)
pyroxene2020(20).jpg

Aegirine crystal (zoned basal section) in a alkaline syenite from Mnt. Flora, Lovozero massif, Kola, Russia. XPL image, 10x (Field of view = 2mm)
brandbeerg(3).jpg

Aegirine (grass-green) crystals. Brandberg Complex (Namibia). PPL image, 2x (Field of view = 7mm)
brandbeerg(4).jpg

Aegirine (high interference colors) crystals in a fine-grained matrix made of quartz and feldspar (I order gray). Brandberg Complex (Namibia). XPL image, 2x (Field of view = 7mm)
brandbeerg(5).jpg

Aegirine (grass-green) crystals. Brandberg Complex (Namibia). PPL image, 2x (Field of view = 7mm)
brandbeerg(6).jpg

Aegirine (high interference colors) crystals in a fine-grained matrix made of quartz and feldspar (I order gray). Brandberg Complex (Namibia). XPL image, 2x (Field of view = 7mm)
brandbeerg(12).jpg

Aegirine (grass-green) crystals. Brandberg Complex (Namibia). PPL image, 2x (Field of view = 7mm)
brandbeerg(13).jpg

Aegirine (high interference colors) crystals in a fine-grained matrix made of quartz and feldspar (I order gray). Brandberg Complex (Namibia). XPL image, 2x (Field of view = 7mm)
foidolitealeucite(5).jpg

Leucite (clorless) and clinopyroxene crystals in a foidolite with leucite. PPL image, 2x (Field of view = 7mm)
foidolitealeucite(6).jpg

Leucite and clinopyroxene crystals in a foidolite with leucite. XPL image. 2x (Field of view = 7mm)
foidolitealeucite(7).jpg

Leucite (clorless) and clinopyroxene crystals in a foidolite with leucite. PPL image, 2x (Field of view = 7mm)
foidolitealeucite(8).jpg

Leucite and clinopyroxene crystals in a foidolite with leucite. XPL image 2x (Field of view = 7mm)
foidolitealeucite(9).jpg

Leucite (clorless) and clinopyroxene crystals. PPL image, 2x (Field of view = 7mm)
foidolitealeucite(10).jpg

Leucite and clinopyroxene crystals in a foidolite with leucite. XPL image. 2x (Field of view = 7mm)
nefelinolite(3).jpg

Augite (pink), nepheline (colorless) and Apatite (elongated, colorless crystals). Cape Verde. PPL image, 2x (Field of view = 7mm)
nefelinolite(4).jpg

Augite and nepheline (grey). Cape Verde. XPL image, 2x (Field of view = 7mm)
nefelinolite(5).jpg

Augite (pink) and nepheline (colorless). Cape Verde. PPL image, 2x (Field of view = 7mm)
nefelinolite(6).jpg

Augite and nepheline (grey). Cape Verde. XPL image, 2x (Field of view = 7mm)
nefelinolite(2).jpg

Augite and nepheline (grey). Cape Verde. XPL image, 2x (Field of view = 7mm)
nefelinolite(7).jpg

Augite and nepheline (grey). Cape Verde. XPL image, 2x (Field of view = 7mm)
gabbromicroograficoo(2).jpg

Clinopyroxene crystals in a gabbro. PPL image, 2x (Field of view = 7mm)
gabbromicroograficoo(3).jpg

Clinopyroxene crystals in a gabbro. XPL image, 2x (Field of view = 7mm)
gabbromicroograficoo(4).jpg

Clinopyroxene crystals in a gabbro. PPL image, 2x (Field of view = 7mm)
gabbromicroograficoo(5).jpg

Clinopyroxene crystals in a gabbro. XPL image, 2x (Field of view = 7mm)
gabbromicroograficoo(6).jpg

Clinopyroxene crystals in a gabbro. XPL image, 2x (Field of view = 7mm)
gabbroantartide(14).jpg

Resorbed olivine crystal in a gabbro, Antarctica. XPL image, 2x (Field of view = 7mm)
Photo
gabbroatitanoaugite(2).jpg

Coarse-grained augite crystals and sericitized plagioclase in a augite-bearing gabbro. PPL image, 2x (Field of view = 7mm)/td>
gabbroatitanoaugite(3).jpg

Coarse-grained augite crystals and plagioclase in a augite-bearing gabbro. XPL image, 2x (Field of view = 7mm)/td>
gabbroatitanoaugite(4).jpg

Coarse-grained augite crystals and sericitized plagioclase in a augite-bearing gabbro. PPL image, 2x (Field of view = 7mm)/td>
gabbroatitanoaugite(5).jpg

Coarse-grained augite crystals and sericitized plagioclase in a augite-bearing gabbro. PPL image, 2x (Field of view = 7mm)/td>
gabbroatitanoaugite(6).jpg

Coarse-grained augite crystals and sericitized plagioclase in a augite-bearing gabbro. PPL image, 2x (Field of view = 7mm)/td>
gabbroatitanoaugite(7).jpg

Coarse-grained augite crystals and sericitized plagioclase in a augite-bearing gabbro. PPL image, 2x (Field of view = 7mm)/td>