[5] The surface of the lens has twelve cavities that were opened during grinding, which would have contained naphtha or some other fluid trapped in the raw crystal.

[6] According to his book, Layard found the lens buried beneath other pieces of glass that looked like the enamel of an object, perhaps made of wood or ivory, that had disintegrated.

[3] The British Museum curator's notes propose that the lens could have been used "as a piece of inlay, perhaps for furniture" and that there is no evidence that the Assyrians used lenses for their optical qualities (e.g., for magnification, for telescopy, or for starting fire).

A similar object was mentioned in The Epic of Ishtar and Izdubar, Column IV, Coronation of Izdubar, written about 2,000 BCE, of which the 10th stanza reads:The King then rises, takes the sacred glass, And holds it in the sun before the mass Of waiting fuel on the altar piled.

The centring rays—the fuel glowing gild With a round spot of fire and quickly spring Above the altar curling, while they sing[8][9]