rock crystal

plural rock crystals

1. countableuncountableA clear, colorless form of the silica-based mineral quartz.

   At New Year he had given Anne a present of silver forks with handles of rock crystal.

   2009, Hilary Mantel, Wolf Hall, London: Fourth Estate, Part 4, Chapter 1, p. 296

   4 more examples

   […] I have for Trials sake taken Lumps of Rock Crystal, and Heating them Red hot in a Crucible, I found according to my Expectation, that being Quench’d in Fair water, even those that remain’d in seemingly entire Lumps, exchang’d their Translucency for Whiteness […]

   1664, Robert Boyle, chapter 1, in Experiments and Considerations Touching Colours, London: Henry Herringman, page 114

   […] I saw his Body, in Episcopal Robes, lying upon the Altar in a Shrine of Rock-Crystal.

   1718, Joseph Addison, Remarks on Several Part of Italy, London: J. Tonson, pages 22–23

   […] there in the laboratory we beheld a larger edition of the little mechanism which we had seen vanish from before our eyes. Parts were of nickel, parts of ivory, parts had certainly been filed or sawn out of rock crystal.

   1895, H. G. Wells, chapter 1, in The Time Machine, New York: Henry Holt, page 24

   I wondered whether I ought to speak to Brideshead, but that grim, rock-crystal mask forbade all confidence.

   1945, Evelyn Waugh, chapter 5, in Brideshead Revisited, Boston: Little, Brown, page 131

   Synonyms: clear quartz, pure quartz