PRESELI BLUESTONE (SPOTTED DOLERITE) - Preseli Hills, Pembrokeshire
« back'PRESELI BLUESTONE'
Spotted dolerite famous for its connection with Stonehenge
Preseli Hills, Pembrokeshire, Wales
Preseli Bluestone, also known as ‘Spotted Dolerite’, is an igneous rock formed during the Ordovician period, about 400 million years ago. It is found only in Pembrokeshire's Preseli Hills. Although it might not look blue, it does have a bluish tinge when freshly broken or when wet.
The stone is notable for the white patches of feldspar crystals which are the result of the rock being reheated and recrystallised (metamorphosed) during the Caledonian mountain building episode.
Preseli Bluestone is famous because it was one of the rocks used to build Stonehenge. Although most of Stonehenge is built of sarsen stones, the bluestone was used for many of the smaller upright stones. For many years there has been a debate about how these rocks, each weighing between 2 and 5 tons, were transported from Wales to the Salisbury Plain; were they transported by humans or carried by ice during the Ice Age?
This is a very nice example, weighing over half a kilogram. Smaller pieces are available - please enquire.
Important note: The site where the Preseli bluestone is exposed is part of the Mynydd Preseli Site of Special Scientific Interest and Preseli Special Area of Conservation and therefore no collecting is permitted. This example was from an isolated boulder found outside the protected area that was carried to its present location by glaciers during the Ice Age.
Click on a picture for a larger image
Size: 11 x 8 x 8 centimetres
Weight: 540 grams
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