A Victorian carved shell portrait cameo brooch

A Victorian carved shell portrait cameo brooch, probably depicting Benjamin Disraeli (1804-1881) and engraved to the reverse 'Ronca 1866' and with inverted 'R's. 5.5cm high, in fitted case. A carved shell cameo brooch, depicting a finely carved Athena with helmet and wearing the aegis, bearing the head of the Gorgon Medusa. Her attribute, the snake (Prudence), is entwined around her spear. Edge chipped. 4.5cm high, gold frame. And a carved shell cameo depicting Hera wearing her diadem and veil signifying her roles as Queen of Olympus and a marriage divinity. Gold mount and attached to a gilt metal bracelet. The cameo 3.8cm high.