pyroxene: Quick Facts

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Moon rock crystals

Figure 1: Single pyroxene chain, (SiO3)n, in three projections: (A) along the c axis direction, (B) on (100), a plane that intersects the a axis and is parallel to the b and c axes, and (C) along the b axis direction.

Figure 3: (A) Schematic projection of the monoclinic pyroxene structure perpendicular to the c axis. (B) Control of cleavage angles by the I beams in the pyroxene structure.

Uncut (left) and cut jadeite.

A micrograph of an enstatite crystal taken from an ultramatic rock. The thin lamellae of a calcium-rich species, probably pigeonite, have separated from the bronzite; the gray coloration of the host rock betrays its very low calcium content (magnified about 40×).

A micrograph of a twinned crystal of inverted pigeonite from a gabbro.

A micrograph showing augite, seen as brightly coloured thin lamellae with herringbone texture because of the twinned relationship, separated from pigeonite; further cooling has caused the host, gray-coloured enstatite, to change symmetry (inverted and magnified about 22×).

A micrograph showing a sample of inverted pigeonite from a slowly cooled gabbro. The augite lamellae here are relatively wide, separated from the enstatite host (magnified about 70.4×).

Bowen's reaction series

Figure 15: Schematic cross section illustrating the shell structure of the Earth.

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Topics

clinopyroxene pyroxene quadrilateral tschermakite kosmochlor diopside-hedenbergite join jadeite orthopyroxene wollastonite diopside rhodonite amphibole

Basalt sample returned by Apollo 15, from near a long sinous lunar valley called Hadley Rille. Measured at 3.3 years old.

(Bed) Rocks and (Flint) Stones