- a variety of quartz resembling flint.
Origin of hornstone
1720–30; translation of German Hornstein
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for 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.
The shales become dense, highly crystalline rocks of a "hornstone" type, with porphyritic developments of silicate minerals.The Economic Aspect of Geology
C. K. Leith
Another of the dikes of the north-east of Ireland has converted a mass of red sandstone into hornstone.A Manual of Elementary Geology
C17: translation of German Hornstein; so called from its appearance
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