©Lin Yangchen

Microscope: ‘Special Forces’ Olympus BHSP

This website is one of the very few to present meteorite thin section micrographs in both transmitted and reflected light. Analyses are dependent on my progressive study of meteorite mineralogy and may not be error-free. Please contact me if you spot mistakes so I can correct them and make this a better reference for everyone. Also see my terrestrial petrography page and disco lighting videos.

Accession no. R010

Locality: Kerman, Iran
Sample date: 2 April 2016
Method: hand sample
Finder: Timur Valer'evich Kryachko and Khatami Majid, Iranian-Russian expedition

Macroscopic description

Gandom Beryan meteorite. Ordinary chondrite of primitive material from the early Solar System. Covered by dark brown fusion crust. Weathering grade (see Wlotzka 1993) W1 (light oxidation).

Petrographic analysis

Polished with 0.5 μm diamond paste on 2 mm glass slide with no coverslip
prepared by Timur Kryachko

Class L3 subtype 3.6 (low-iron unequilibrated mineral assemblage slightly metamorphosed). Shock stage S1 (no shock metamorphism). Disco lighting videos: low | high magnification

Going back 4,500,000,000 years to the time when the Solar System was a spinning disc of gas and dust.

Radial pyroxene (RP) chondrule formed by rapid cooling of molten ore, with a porphyritic rim resembling a mediæval stone wall and an opaque outer fine-grained rim of sticky nebular dust that accreted in an environment of turbulence and electrostatic forces and helped chondrules aggregate into larger bodies. Left, transmitted; right, reflected. Top, plane-polarized; bottom, cross-polarized. Bright white patch at upper left of reflected plane-polarized micrograph is metal, probably native iron.

Length slow or positive sign of elongation with 530 nm retardation plate.

Part of a large porphyritic olivine pyroxene (POP) chondrule with occasional glass and opaque grains. Left, transmitted; right, reflected. Top, plane-polarized; bottom, cross-polarized.

A pair of poikilitic pyroxene chondrules with contrasting olivine grain sizes, different twinning and extinction morphologies, and oxidation stains. See video.

Olivine bundled with fibrous material. Left, transmitted; right, reflected. Top, plane-polarized; bottom, cross-polarized. Darker grey phases in reflected plane-polarized light are usually indicative of feldspar compared with the lighter grey silicates.

Cratered cryptocrystalline chrondule with layered bleached rim (evidence of aqueous alteration of parent body) and thin glassy outer rim. Left, transmitted; right, reflected. Top, plane-polarized; bottom, cross-polarized.

Polysomatic barred olivine.

Conoscopic fourier transform optic axis interference figures of a biaxial positive mineral. Numerical aperture 0.80.

An opaque grain in reflected plane-polarized (top) and cross-polarized (bottom) light, possibly composed of kamacite (light bluish grey and isotropic), taenite (cream) and troilite (FeS iron sulphide, tan). Bluish grey phases could also be oxides or chromite. Cross-polarization reveals internal reflections and oxidation weathering that has stained the surrounding silicates.

Meteorite databases & atlases

Marmet meteorites
Derochette meteorite thin sections


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