Important formations of chromite are found at Hagdale and the Heog Hills; steatite occurs at Kleber Geo, and many interesting minerals have been recorded from these islands.
The principal exports are rubber, sugar, ground-nuts and oil seeds, beeswax, chromite (from Rhodesia), and gold (from Manica).
There is chromite in the black sands of the sea-coast and the banks of the larger rivers.
Ostwald (ibid., 1900, 35, pp. 33, 204) has observed that on dissolving chromium in dilute acids, the rate of solution as measured by the evolution of gas is not continuous but periodic. It is largely made as ferro-chrome, an alloy containing about 60-70% of chromium, by reducing chromite in the electric furnace or by aluminium.
Thechromites maybe looked upon as salts of chromium sesquioxide with other basic oxides, the most important being chromite (q.v.).