#petrography

[locket-full-of-lazuli]

Biaxial minerals, how I long to understand you

[srlgemstone]

Opalized Petrified Wood

[srlgemstone]

Amazing Collawood Pieces

[perfectcleavage]

Monte Duria Peridotite

One of my favorite thin section samples in our lab. Pyroxene with exsolution lamellae and some stunning berlin blue chloritization.

[grittyghoul]

I made these petrography affirmations

[grittyghoul]

The cursed beast from my dream

[noosphe-re]

Petrographic thin-sections of titanite (Ttn), muscovite (Ms) and calcite (Cal) grains intergrown with larger plagioclase (Pl) crystals in plane-polarized light (A,C) and under crossedpolarized light (B,D); corundum (Crn) intergrowths with margarite (Mrg) and plagioclase crystals (E,F), plane-polarized light. (source)

[noosphe-re]

Petrography and evidence for melt^peridotite reactions in the TLP. (a) Photomicrograph of a Cpx porphyroclast with Opx exsolution providing evidence of sub-solidus cooling from high temperatures. (b) Two-pyroxene^spinel symplectite after garnet in sample HR þ 12 indicates a decompressional history from the garnet peridotite facies. (c) Back-scattered electron image showing the typical peridotite mineral assemblage in the TLP. (d) Photomicrograph illustrating highly strained peridotite textures such as the development of subgrain boundaries in Opx and kink bands in Ol, and showing sub-solidus plagioclase. (e) Photomicrograph of HR 0 in cross-polarized light highlighting the pyroxene dissolution reaction texture (marked with yellow lines) forming secondary olivine. (f) Photomicrograph of HR þ 5 in cross-polarized light. Reaction rims of Opx around the primary porphyroclastic olivine are highlighted with yellow lines. (g) Crystallization of fine aggregates of Cpx, Opx and Ol interstitial to pyroxene porphyroclasts, formed as a result of melt^rock reaction. (h) Presence of melt ribs between Cpx porphyroclasts indicating melt migration pathways. (source)