Giant quartz

A reported giant single quartz crystal from Brazil was about 6.1 m long; the literature gives an estimated mass of about 39.9 tonnes, though the review author cautioned that this estimate may be too low. It was not a spectrometer prism. Quartz was indeed used in spectroscopic instruments, but prism specimens are centimetre-scale: for example, the Whipple Museum in Cambridge records a quartz spectroscope prism 53 mm long. The source item appears to conflate a giant natural crystal with the use of much smaller optical components.