http://earthwise.bgs.ac.uk/index.php?action=history&feed=atom&title=File%3AP519580.jpg 2026-07-03T00:03:39Z Revision history for this page on the wiki MediaWiki 1.42.3 http://earthwise.bgs.ac.uk/index.php?title=File:P519580.jpg&diff=31746&oldid=prev 2017-07-29T14:53:24Z

<p>User created page with UploadWizard</p> <p><b>New page</b></p><div>=={{int:filedesc}}==<br /> {{Information<br /> |description={{|1=Specimen of roofing slate quarried from Ballachulish, Argyllshire, Scotland. Dark grey slate with relatively smooth cleavage surface and a few large pyrite crystals. The specimen is of Precambrian, Dalradian age. British Geological Survey Petrology Collection sample number EMC 5756. A number of different slate varieties were produced from Ballachulish, depending on their colour and texture. This slate is marked&#039;Ordinary&#039;, being a particularly dark and plain type. The specimen itself has not been dressed. Slate dressing involves splitting the slate rock along the cleavage to give a suitable thickness, then cutting the edges to give the correct shape. Traditionally this was done by hand, using a hammer and chisel for the splitting, and a slate knife for cutting. Historical records refer to the production of slates from Easdale and Caithness in the 16th and 17th centuries, which were used for the roofs of Highland castles. P519580.}}<br /> |date=2017-07-29 15:51:24<br /> |source=British Geological Survey<br /> |author=British Geological Survey<br /> |permission=<br /> |other versions=<br /> }}<br /> <br /> =={{int:license-header}}==<br /> {{subst:Custom license marker added by UW}}<br /> {{BGS}}<br /> <br /> [[Category:Uploaded with UploadWizard]]</div>

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