Found 2 items, similar to hornstone.
English → English (WordNet) Definition: hornstone hornstone n : a fine-grained metamorphic rock formed by the action of heat on clay rocks [syn: hornfels]
English → English (gcide) Definition: Hornstone Hornstone \Horn"stone`\, n. (Min.) A siliceous stone, a variety of quartz, closely resembling flint, but more brittle; -- called also chert. [1913 Webster]