Spinel dunite from Samani, Hokkaido, Japan.
FOV=ca.5 mm #thinsection #petrology #petrography #polarizingmicoscope
@nishimoto.rocks
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@nishimoto.rocks
@hydromo.bsky.socialThin sections (~30 μm) under crossed polars let us read minerals inside an opaque rock — quartz extinguishes every 90°.
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