[5] G. hamiltonii is mainly black with small yellowish or white spots, and a much-elevated carapace, with three interrupted keels or series of nodose prominences corresponding to the vertebral and costal shields.
The posterior border of the carapace is strongly serrated in young, but feebly in the adult.
The shell is dark brown or blackish, elegantly marked with yellow spots and radiating streaks, and the soft parts are dark brown or blackish, with round yellow spots, largest on the head and neck.
[7] G. hamiltonii preys predominately upon snails, but also eats dragonfly larvae, other insects, freshwater crustaceans, and other animal and vegetable food items.
[1] G. hamiltonii is found in southern Pakistan (Indus, Ganges, Brahmaputra River drainages), northern India (Assam, Bihar, Jammu, Meghalaya, Punjab, Rajasthan, Uttar Pradesh, West Bengal), Sri Lanka, and Bangladesh.