A important and comprehensive collection of mineralogical microscope slides, circa 1910, from South African gold and diamond mines, in five mahogany cases of twelve trays, each originally containing four slides, two cases with labels for J. Swift & Son Ltd., 81 Tottenham Court Road, London W1, including thin sections of Kimberlite volcanic pipes, dykes and sills, host rocks and xenoliths, each slide simply labelled with the mine including De Beers Consolidated Mines Ltd. Mines:- Kimberley De Beers, Wesselton, Bultfontein and Du Toits Pan, all near the town of Kimberley, Voorspoed near Kroonstad and Koffyfontein, other mines include Jagersfontein, Roberts Victor, Klipfontein, Monastery and the Premier (famous as the source of the 3,106 carat Cullinan Diamond found on 20th January 1905), each slide numbered, each case -- 10in. (25.l4cm.) wide