noun ·Rare ·Advanced level

Definitions

Noun

1. 1
   Any of a series of contact metamorphic rocks that have been baked and indurated by the heat of intrusive igneous masses and rendered massive, hard, splintery, and in some cases exceedingly tough and durable. countable, uncountable
2. 2
   a fine-grained metamorphic rock formed by the action of heat on clay rocks wordnet

Synonyms

All synonyms

hornstonelydianite

Etymology

Borrowed from German Hornfels, literally "horn stone", after its frequent association with glacial "horn peaks" in the Alps.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.