The Moonstone.

The Moonstone (1868) by Wilkie Collins is a 19th-century British epistolary novel. It is generally considered to be the first detective novel, and it established many of the ground rules of the modern detective novel. The story was originally serialised in Charles Dickens' magazine All the Year Round. The Moonstone and The Woman in White are widely considered to be Collins' best novels, and Collins adapted The Moonstone for the stage in 1877, although the production was performed for only two months. The Moonstone of the title is a diamond, not to be confused with the semi-precious moonstone gem. It gained its name from its association with the Hindu god of the moon Chandra. It was said to be protected by hereditary guardians on the orders of Vishnu, and to wax and wane in brilliance along with the light of the moon.