Emerald-class corvette

The Emerald-class corvettes were a class of six composite screw corvettes built for the Royal Navy in the mid-1870s. The Opal was built by contract under the 1873-74 Programme, and Turquoise, Ruby, Tourmaline and Emerald under the 1874-75 Programme - the first three also by contract, while Emerald was dockyard-built at Pembroke. The final ship (Garnet) was also dockyard-built at Chatham under the 1875-76 Programme.