The Nimrud lens is a 3000 year old piece of rock crystal, which was unearthed by Austen Henry Layard at the Assyrian palace of Nimrud, in modern-day Iraq.[1] It may have been used as a magnifying glass, or as a burning-glass to start fires by concentrating sunlight. Assyrian craftsmen made intricate engravings, and could have used such a lens in their work. The Nimrud lens is on display in the British Museum.