Orthopyroxene - XYZ2O6

Optical properties:

• Colour and Pleochroism: Colourless
• Form: crystals form stubby prisms elongate along the c-axis, basal sections are 4 or 8 sided and show two cleavages at 90°
• Cleavage: typical pyroxene cleavages 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: low interference colors, straigth extinction.

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




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ortopirossenii(3).jpg

Orthopyroxene crystal in a Dacite. XPL image , 10x (Field of view = 2mm)
ortopirosseno2012a(2).jpg

Orthopyroxene crystal in a Dacite. XPL image , 10x (Field of view = 2mm)
ortopirossenii(2).jpg

Orthopyroxene crystal in a Dacite. PPL image , 10x (Field of view = 2mm)
ortopirossenii(4).jpg

Orthopyroxene crystal with clinopyroxene rim in a Dacite. XPL image , 10x (Field of view = 2mm)
ortopirossenii(5).jpg

Orthopyroxene crystal with clinopyroxene rim in a Dacite. XPL image , 10x (Field of view = 2mm)
ortopirossenii(6).jpg

Orthopyroxene crystal. PPL image , 10x (Field of view = 2mm)
ortopirossenii(7).jpg

Orthopyroxene crystal with clinopyroxene rim in a Dacite. XPL image , 10x (Field of view = 2mm)
ortopirossenii(8).jpg

Orthopyroxene crystal with clinopyroxene rim in a Dacite. XPL image , 10x (Field of view = 2mm)
ortopirossenii(9).jpg

Orthopyroxene crystal with clinopyroxene rim in a Dacite. XPL image , 10x (Field of view = 2mm)
ortopx2012a(3).jpg

Orthopyroxene crystal. PPL image , 2x (Field of view = 7mm)
ortopx2012a(4).jpg

Orthopyroxene crystal. XPL image , 2x (Field of view = 7mm)
ortopx2012a(41).jpg

Orthopyroxene crystal. XPL image , 2x (Field of view = 7mm)
ortopirosseno2012a(4).jpg

Orthopyroxene crystal. XPL image , 10x (Field of view = 2mm)