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



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.
• Optical Mineralogy : The Nonopaque Minerals by Phillips / Griffen
• Ron H. Vernon (2004): A pratical guide to rock microstructure. Cambridge editore
• David Shelley (1983): Igneous and metamorphic rocks under the microscope. Campman & Hall editori




Aegirine
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Aegirine crystal in a pantelleritic ignimbrite. Pantelleria island, Italy. PPL image , 2x (Field of view = 7mm)
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Aegirine crystal in a pantelleritic ignimbrite. Pantelleria island, Italy. PPL image , 2x (Field of view = 7mm)
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Aegirine crystal in a pantelleritic ignimbrite. Pantelleria island, Italy. PPL image , 2x (Field of view = 7mm)
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Aegirine crystal in a pantelleritic ignimbrite. Pantelleria island, Italy. PPL image , 2x (Field of view = 7mm)

Augite
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Augite (pink) crystal. PPL image , 2x (Field of view = 7mm)
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Augite (pink) crystal. PPL image , 2x (Field of view = 7mm)
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Augite crystal. XPL image , 2x (Field of view = 7mm)
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Augite crystal. PPL image , 2x (Field of view = 7mm)
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Augite crystal. XPL image , 2x (Field of view = 7mm)
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Augite crystal. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a essexsite from Kaiserstuhl, Germany. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a essexsite from Kaiserstuhl, Germany. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a essexsite from Kaiserstuhl, Germany. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a essexsite from Kaiserstuhl, Germany. XPL image , 2x (Field of view = 7mm)
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Augite crystals in a essexsite from Kaiserstuhl, Germany. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a essexsite from Kaiserstuhl, Germany. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)
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Augite crystals in a foidite from Cape Verde island. PPL image , 2x (Field of view = 7mm)


Diopside
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Diopside crustals in a volcanic rock from Amiata volcano (Italy). PPL image , 2x (Field of view = 7mm)
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Diopside crustals in a volcanic rock from Amiata volcano (Italy). PPL image , 2x (Field of view = 7mm)
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Diopside crustals in a volcanic rock from Amiata volcano (Italy). PPL image , 2x (Field of view = 7mm)
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Diopside crustals in a volcanic rock from Amiata volcano (Italy). PPL image , 2x (Field of view = 7mm)
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Diopside crustals in a volcanic rock from Amiata volcano (Italy). XPL image , 2x (Field of view = 7mm)
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Diopside crustals in a volcanic rock from Amiata volcano (Italy). XPL image , 2x (Field of view = 7mm)