Rock crystal Rock crystal is a transparent quartz, typically in the form of colourless hexagonal crystals. On the Mohs scale of hardness, it scores highest, at 7. Roman naturalist Pliny the Elder believed rock crystal to be water that had permanently frozen after great lengths of time.[1] The mineral has been used for luxurious objects of great value and symbolised the wealth and status of its owners since prehistory. Notable artefacts have been found in numerous Mycenaean and Minoan archaeological contexts datable to the Bronze Age in Greece, around 1750–1050 BC. Pliny the Elder also discusses the properties of rock crystal in his Natural History, published around AD 77 and one of the largest single works to have survived from the Roman Empire. In it, he claims that rock crystal was more valuable than gold in the ancient world. Rock crystal remained popular for use in luxury objects from the Greek and Roman periods through the 1600s, when rock crystal objects are documented in the courts of Europe. For an example of a pristine rock crystal–cased watch, see Edward East's resplendent Miniature Rock Crystal Watch, made around 1635. End Note [1] See Pliny’s The Natural History, Book 37, Chapter 9.
