Spinel Group Mineral

A Spinel Group Mineral is a cubic mineral with a general formula AB₂O₄ (where A and B represent divalent and trivalent cations, respectively).

Context:
- It can include minerals with varying compositions, such as magnesium, iron, zinc, chromium, and aluminium in the cation sites.
- It can form in the cubic crystal system, often producing octahedral or rounded crystals.
- It can exhibit diverse colors based on the cation composition, including red, green, blue, and black.
- It can be found in metamorphic, igneous, and sedimentary environments, often associated with ultramafic rocks or contact metamorphism.
- It can serve as a geochemical indicator in studying the conditions of rock formation, especially in petrology.
- It can range from common forms like spinel (MgAl₂O₄) to rarer varieties such as chromite (FeCr₂O₄) and gahnite (ZnAl₂O₄).
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Example(s):
- Spinel, which is the magnesium-aluminium member of the group and a common gemstone.
- Chromite, which is the iron-chromium member and an important ore of chromium.
- Gahnite, which is the zinc-aluminium member and a rare accessory mineral in pegmatites.
- Hercynite, which is the iron-aluminium member found in metamorphic rocks.
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Counter-Example(s):
- Perovskite Group Minerals, which crystallize in different systems and have different formulas.
- Garnet Group Minerals, which also have variable compositions but lack the AB₂O₄ formula structure.
- Quartz, which is a common silicate mineral that does not belong to the spinel group or cubic system.
See: Spinel, Cubic Crystal System, Oxide Minerals, Mineralogy, Chromite, Petrology.

References

(Wikipedia, 2024) ⇒ https://en.wikipedia.org/wiki/Spinel_group Retrieved:2024-12-15.
- Spinel Group Minerals are a class of cubic oxide minerals characterized by the formula AB₂O₄. They are named after their most common member, spinel (MgAl₂O₄), and are significant in geology and gemology.^[1]