This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
The Quarterly journal of the Geological Society of London . ASSOCIATED ROCKS OF THE LIZARD DISTRICT red variety for towards the outside it exhibits perfectly the change into the red variety have specimens about inches long red at one end and green at the other Hence the alteration may not be so deepseated as from its uniformity