#eclogite

[camblorite]

Eclogite

Eclogites are essentially composed of omphacite (pyroxene) and pyrope/almandine (garnet). They are formed under high pressure and high temperature.

[weekendviking]

Seam flatteners in Rodingite, top, and Peridotite, bottom. Moment of 'Why Not' today as I did final packdown tasks in the lab before leaving after 15 years at that job. God I love diamond tools.

The Rodingite has come out particularly nice. This one is mostly grossular garnet, but with some pale white omphacite as a decompression metamorphism product from the grossular. The opaque is probably a chromite, but I'm not sure, I haven't made a thin section of this material, and now, won't get the chance.

[aellivi]

Another gem sketch dump? From me? No way.

[drrockclub]

Eclogite

This is a thin section of the eclogite, a very high-grade metamorphic rock that forms deep within Earth’s crust. For this reason, it is quite rare to find it on the surface. Red and rhomb shaped crystals are garnets whereas bluish/green minerals among them is omphacite, a rare mineral which forms at very high-pressure conditions.

This rock has characteristic red-green physical appearance making it quite a pretty outcrop. It is also very dense/heavy and for this very reason it is known to drive plate tectonics, bring the continents on our planet together.

Example from the hearth of the Himalaya, Tso Moriri.

[earthstory]

Eclogite

This is a polished piece of eclogite held in a museum in Scotland: the red grains are probably slightly less than half a centimeter in diameter. Eclogite is a rock that has often-brilliant green and red minerals. The greenish minerals here are pyroxenes and the reddish minerals are garnets. Eclogite holds a special place in the Earth; it's the rock that drives plate tectonics. When ocean crust is squeezed to high pressure and taken to high enough temperatures, as in a subduction zone, it turns into eclogites very much like this. The remarkable thing about eclogite for the Earth is that when it forms, it is denser than the surrounding mantle and will therefore sink. Once a piece of oceanic crust starts turning to eclogite, it will sink deep into the mantle. This rock, therefore, is a big part of the reason why we have plate tectonics on Earth. Every mountain range, valley, mineral resource, and natural wonder we see on this planet is at least influenced strongly by the existence of eclogite. -JBB Image credit: https://www.flickr.com/photos/dun_deagh/6865437290

[geologyandstuff]

Not sure if I have posted this one before but this is eclogite in thin section. 4x

Garnet with a pyroxene ground mass

[green-algae]

Thin sections [a geological sample examined with a polarizing metrographic microscope or similar microscope] of metamorphic rocks photographed by J.M. Derochette. From top to bottom, we see lazurite from Afghanistan, amphibolite from France, and eclogite with quartz.

[hematitehearts]

Pyrope Garnet

Locality: Eclogite outcrops, Jianggalesayi area, Qiemo (Qerqen; Cherchen) Co., Bayin'gholin (Bayingolin; Bayinguoleng) Autonomous Prefecture, Xinjiang (Xinjiang-Uygur) Autonomous Region, China