Ships Cover for the Gem class third class protected cruisers HMS Amethyst (1903), HMS Diamond (1904), HMS Sapphire (1904) and HMS Topaze (1903). The documentation mainly comprises the initial design proposals and accompanying development discussions for the new design, a brief development history of third class cruisers in general and details of the vessels concerned, statements of dimensions and estimates of weights, stability calculations, details of ships fittings and equipment, schemes of complement, details of tenders and correspondence with the contractors, cost estimates, details of armament and ammunition allowance, and details of alterations made to members of the Gem class. The earliest papers date from March 1899 at the very beginning of the design phase and the last from August 1918 at the concluding years of the class' service.