Cooler and harder than glass, but softer than a diamond: rock crystal has always been regarded as an unusual material. Countless legends have grown up around its origins and its remarkable strengths. At the latest since Antiquity, rock crystal has played an important part as a remedy, for fortune-telling, in the Church and at courtly banquets. Breath-taking artworks have been assembled in this publication.

For a long time, people assumed that rock crystal was water that had been solidified to form eternal ice. They used it to create objects with the aura of the divine. From Antiquity to the end of the Middle Ages, the spectrum of works extended from vessels for sacred and profane objects to crosses, chess pieces, amulets, chilling balls, badges of office and magnifying glasses. The facets of rock crystal as a material, its processing, uses and symbolic interpretation are illustrated from the perspective of art, mineralogy, archaeology, philology and optics.