This flask is an example of cameo decoration, known since the first century AD, and practised in the early Islamic period in Iran and Egypt. Cameo decoration is an extension of the technique of cut glass. First, the glass object is partially blown into its intended shape. Then it is dipped into molten coloured glass (in this case green), and blown into its final shape. When cooled, the coloured outer layer is cut away to make a design, revealing the original glass beneath, leaving the desired coloured pattern carved in relief on the surface. The relief-carved cameo hare on this flask has led to suggestions that it was produced in Fatimid Egypt (969-1171), rather than Iran as has also been proposed. Hares are a recurrent motif in Fatimid art, and are found in wood-carving, ivory, ceramics and glass.