Definition of "hornstone" []

• Hornfels (noun)

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• "Chert is sometimes called hornstone; also the term chert is often applied to any impure flinty rock, including jaspers."
• ""hornstone" type, with porphyritic developments of silicate minerals."
• "During a ride to a natural tank amongst these rocky elevations, I passed from the alluvium to the sandstone, and at once met with all the prevailing plants of the granite, gneiss, limestone and hornstone rocks previously examined, and which I have enumerated too often to require recapitulation; a convincing proof that the mechanical properties and not the chemical constitution of the rocks regulate the distribution of these plants."