a variety of quartz resembling flint.
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How to use hornstone in a sentence
Dark grey porphyritic hornstone, approaching to compact felspar, with imbedded crystals of felspar.
I also picked up a detached mass of argillaceous oxide of iron, and some fragments of striped hornstone.
About ten miles north of this point, the upper calcareous, or surface rock, embraces nodules of hornstone.
The occurrence of a hard variety of hornstone, which is not flint, is apparently confined to the compact, fetid variety.
Among the rubbish of the diggings, fragments of hornstone occur.
British Dictionary definitions for hornstone
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012