Saturday, 18 May 2013

Iona Silverstone

The island of Iona is about 1km off the south west tip of Mull. it is world famous for its religious significance as one of the earliest centres of Christianity in Britain. Among geologists it is also known for being a source of Marble from a quarry on the southern end of the island. Less well known is another outcrop on the western side. This is different from the southern marble as it contains phlogopite mica. This gives the stone from here a "sparkle" and is known as Silverstone.
The outcrop is small and difficult to find. The marble does not occur in large slabs so this area has been little worked. It is quite distinct from any other marble I know. It contains Serpentine (from forsterite), diopside, brucite, and phlogopite in a calcite matrix.
Directios to the site can be provided for anyone interested in visiting it, please contact me via my contact page on It is a fine walk in good weather, from the ferry you need to allow 4 hours for the round trip, as there is plenty of interesting geology (lewisian) and to distract you, and beautiful views to photograph.

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