Diamond inclusions

[1][4] P-type and E-type inclusions can be distinguished based on the content of specific materials in the trapped mineral.

This suggests that lithospheric P-wave speeds can be used, perhaps elsewhere as well as in Southern Africa, to map the distribution of different diamond source regions.

[11] However, these additional classifications are harder than the lithospheric inclusions due to the rarity of samples, small grain size, and difficulties in recognizing the original mineral assemblages under deep-mantle conditions.

The after-formed minerals can crystallize along diamond fractures or the pre-existing protogenetic/syngenetic inclusions may have been altered into new material.

[1] Mineral inclusions can preserve materials formed under the extreme environments in Earth's mantle back to surface conditions.

[18] The discovery was surprising due to the extreme conditions necessary to synthesize davemaoite which made it seem unlikely that it could be preserved at the Earth's surface.

[1] Fluid microinclusions mostly contain carbonates with the silicate or halides forming the silicate-carbonate or halide-carbonate assemblages.

[25] In the diamond-forming conditions of high pressures and temperatures, hydrous silicate melt and the aqueous fluid make a single-phase supercritical mixture.

[1] Non-destructive elastic methods such as micro-Raman spectroscopy, strain birefringence analysis, and single-crystal X-ray diffraction are used to estimate the pressure-temperature conditions of the material inside the diamond while minimizing the sample damage.

Garnet inclusion in the host diamond.
Chromium vs. Calcium content of various inclusions. Eclogite (i.e. garnet-bearing) inclusions in diamond contain less Cr 2 O 3 whereas peridotite ( lherzolite and harzburgite ) garnet inclusions have less CaO. Eclogite and peridotite are the two main parental mantle rocks and wehrlite and websterite are minor types. [ 1 ] [ 2 ] [ 3 ]
Tomographic image of the lithospheric mantle obtained from the P-wave data. Red squares represent eclogitic and green squares represent peridotitic inclusions. [ 10 ] [ 9 ]
Examples showing the imposition of the host diamond's morphology on the included mineral in syngenetic inclusions. (a) Inclusion of olivine in diamond with their faces imposed by octahedral (o) and cubic (c) shapes common in diamond. (b) Diamond with several olivine inclusions with faces parallel to the octahedral diamond face. [ 1 ] [ 12 ] [ 13 ]