rock crystal

transparent quartz, especially when colorless.

Origin of rock crystal

First recorded in 1660–70

The cover fell open, and he glanced down at the intricate etched lines and curves on the rock-crystal inner face of the locket.

The Saracen: Land of the Infidel |Robert Shea
You may not know it by that name, but it is that shining, flinty substance you see in sand and rock-crystal.

Round-about Rambles in Lands of Fact and Fancy |Frank Richard Stockton
More varied are the allusions to rock-crystal or crystal, as the poet calls it.

Shakespeare and Precious Stones |George Frederick Kunz
With the glass bowls was discovered a rock-crystal lens, with opposite convex and plane faces.

Discoveries among the Ruins of Nineveh and Babylon |Austen H. Layard

Objects in rock-crystal have the inconvenience of being very expensive.

Metapsychical Phenomena |J. Maxwell

rock crystal

a pure transparent colourless quartz, used in electronic and optical equipment. Formula: SiO 2