Metamorphic Rocks
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Glasgow Museums has a collection of approximately 600 specimens of metamorphic rock. These are almost exclusively from Scotland, particularly the Highlands. Among Scottish material rocks from the Dalradian metamorphics of the Southern and Grampian Highlands dominate. The rock types represented include examples of slate, which was quarried for roofing at various localities, schist, quartzite, phyllite, marble, metagreywacke and schistose grit. There are also smaller numbers of the Moine rocks of the northern Highlands and of Lewisian of the north-west Highlands and Hebrides, which are all of Precambrian age with some of the Lewisian gneiss being almost 3 billion years old. There is a small collection of mylonite from the Moine Thrust Belt and other fault zones. The collection also contains examples of marble, including cut and polished ornamental varieties, which originate from a number of different countries. Metamorphic rocks are one of the three major groups of rocks. They are formed by the alteration of pre-existing rocks by heat and pressure within the Earth’s crust.
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