Definition of hornfels in English:



  • A dark, fine-grained metamorphic rock consisting largely of quartz, mica, and particular feldspars.

    ‘The slate, where thermally metamorphosed, has been turned into siliceous hornfels and mica schist.’
    • ‘As a result, contact metamorphic minerals grow in random interlocking patterns giving rise to hornfels, a tough rock with no direction along which it will split preferentially.’
    • ‘These are actually pseudomorphs of sericite (a fine-grained white mica) after cordierite and are found included in hornfels or slate as a product of contact metamorphism.’
    • ‘For scheelite-dominated deposits, there is the formation of marbles and locally extensive tremolite, silicification, and the development of extensive skarn and hornfels zones.’
    • ‘The hornfels can be very friable, as are the sakura ishi, which makes it easy to find nice crystal sections but difficult to collect matrix specimens.’



/ˈhôrnfelz/ /ˈhɔrnfɛlz/


Mid 19th century from German, literally ‘horn rock’.