Conglomerate

Conglomerates are sedimentary rocks composed of more than 50% particles that are larger than 2 mm.

The photos above are under crossed polarizers and with a field of view of 6.5 mm. On the left a polycrystalline quartz grain (center and right of photo) and a chert grain (left edge of photo) are in a matrix of sparry calcite cement. On the right, a large chert grain (right edge of photo) and a sandstone grain (lower left) are in a matrix of opaque hematite.

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