Definition of "rock crystal" [rock crystal]

• Colorless transparent quartz, used in optical instruments and as a semiprecious gemstone. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "But then she always added a heavy piece of religious jewellery: a huge gold rosary, an Agnus Dci of rock crystal engraved with the Passion."
• "Above them hung a resplendent bronze dore chandelier with chains of rock crystal gracing filigree arms."
• "This hostility was further increased by various controversies which resulted in differences of opinion, such as the contention between Boscovich and Rochon regarding priority in the invention of the rock crystal prismatic micrometer."