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  2. Tholeiitic magma series - Wikipedia

    en.wikipedia.org/wiki/Tholeiitic_Magma_Series

    AFM diagram showing the relative proportions of the oxides of alkalis (A), iron (F), and magnesium (M), with arrows showing the compositional change path of the magmas in the tholeiitic and the calc-alkaline magma series (BT=tholeiitic basalt, FB=ferro-basalt, ABT=tholeiitic basaltic andesite, AT=tholeiitic andesite, D=dacite, R=rhyolite, B=basalt, AB=basaltic andesite, A=andesite; dashed line ...

  3. Interference colour chart - Wikipedia

    en.wikipedia.org/wiki/Interference_colour_chart

    Michel-Lévy interference colour chart issued by Zeiss Microscopy. In optical mineralogy, an interference colour chart, also known as the Michel-Levy chart, is a tool first developed by Auguste Michel-Lévy to identify minerals in thin section using a petrographic microscope.

  4. Fayalite - Wikipedia

    en.wikipedia.org/wiki/Fayalite

    Fayalite (Fe 2 SiO 4, commonly abbreviated to Fa) is the iron-rich end-member of the olivine solid-solution series. In common with all minerals in the olivine group, fayalite crystallizes in the orthorhombic system (space group Pbnm) with cell parameters a 4.82 Å, b 10.48 Å and c 6.09 Å.

  5. Magnetite - Wikipedia

    en.wikipedia.org/wiki/Magnetite

    Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe 2+ Fe 3+ 2 O 4. It is one of the oxides of iron, and is ferrimagnetic; [6] ...

  6. Spinel group - Wikipedia

    en.wikipedia.org/wiki/Spinel_group

    A and B can also be the same metal with different valences, as is the case with magnetite, Fe 3 O 4 (as Fe 2+ Fe 3+ 2 O 2− 4), which is the most abundant member of the spinel group. [3] Spinels are grouped in series by the B cation. The group is named for spinel (MgAl 2 O 4), which was once known as "spinel ruby". [4] (Today the term ruby is ...

  7. Magnetic skyrmion - Wikipedia

    en.wikipedia.org/wiki/Magnetic_skyrmion

    where p describes the magnetisation direction in the origin (p=1 (−1) for (=) = ()) and W is the winding number. Considering the same uniform magnetisation, i.e. the same p value, the winding number allows to define the skyrmion (()) with a positive winding number and the antiskyrmion (()) with a negative winding number and thus a topological charge opposite to the one of the skyrmion.

  8. Gabbro - Wikipedia

    en.wikipedia.org/wiki/Gabbro

    Gabbro specimen Photomicrograph of a thin section of gabbro. Gabbro (/ ˈ ɡ æ b r oʊ / GAB-roh) is a phaneritic (coarse-grained and magnesium- and iron-rich), mafic intrusive igneous rock formed from the slow cooling magma into a holocrystalline mass deep beneath the Earth's surface.

  9. Iron (II,III) oxide - Wikipedia

    en.wikipedia.org/wiki/Iron(II,III)_oxide

    Iron(II,III) oxide, or black iron oxide, is the chemical compound with formula Fe 3 O 4.It occurs in nature as the mineral magnetite.It is one of a number of iron oxides, the others being iron(II) oxide (FeO), which is rare, and iron(III) oxide (Fe 2 O 3) which also occurs naturally as the mineral hematite.