ivory for piano keys, crucifixes, false teeth, and carvings (1880s), rubber for car and bicycle tires (1890s), palm oil for soap (1900s+), copper, tin, zinc, silver, and nickel for industrialization (1910+), diamonds and gold for riches (always), uranium for nuclear bombs (1945), tantalum and tungsten for microprocessors (2000s+), and cobalt for rechargeable batteries (2012+).
