| http://www.w3.org/ns/prov#value | - Application October 15, 1951, Serial No. 251,459 8 Claims. (Cl. 117100) This invention relates to granulated mineral surfacing material and more particularly to roofing granules of such materials as trap, andesite, rhyolite, serpentine, feldspar, argyllite, slate and many other types of rock prepared by grinding the material and screening to the required dimensions, and to the method of forming on
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