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Tuesday, 20 January 2015

Sleek Stone Giant Erratics (2)


Close-up of the texture of giant erratic No 5. From a distance the colour appears greenish-blue.


Close-up of the texture of giant erratic No 3.  This one has a more distinct green colouring.

Would anybody like to hazard a guess at the rock type?  Is this what we would call a quartz-porphyry, or two of them?  Or has it got a different name nowadays?  Rhyolite with feldspar phenocrysts?

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