Cubic graphite pseudomorph after an unknown precursor (some time speculated to be diamond). Exposed from native iron-filled voids in basalt by dissolving the iron in aqua regia. The cube is approximately 0.2 mm across.
This Photo was Mindat.org Photo of the Day - 26th Oct 2008
This Photo was Mindat.org Photo of the Day - 26th Oct 2008
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