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.

They were designed to carry the same armament of fourteen 64-pdr guns as the preceding Amethyst class corvettes from which their design was developed, with two of the guns mounted on rotating slides as bow and stern chasers, and the other twelve guns slide-mounted on the broadsides.

However, only Opal was so completed, and two of her broadside guns were removed following her first commission.

In the early 1880s Tourmaline and Emerald were re-armed with four 6-inch (100-pdr) and eight 5-inch (50-pdr) breach-loader guns.