Tuesday, 6 September 2011

Sandstone ~

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust.
Thank you, Wikipedia, for that nicely succinct definition!  I mention it here in relation to quartzite, which is formed from sandstone.  

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