Minerals available in Tanzania include gold, diamonds, gemstones (such as rubies, aquamarine, tanzanite, sapphire; emerald, rhodolite, opal, zircon, alexandrite, garnets, tourmaline, spinel, peridot, iolite) Iron and Base metals (nickel and cobalt), platinum group metals: (platinum, palladium and Rhodium), Industrial minerals (soda ash, kaolin, salt along the Coast and inland lakes, vermiculites, limestone, silica sands, phosphate, gypsum, mica, dimension stones i.e. granites, travertine, marbles, quartzite) and coal resources. Tanzania is the 4th largest gold producer in Africa after South Africa, Ghana and Mali and is the sole producer of the precious stone Tanzanite in the world. Gold production currently stands at roughly 40 tonnes a year, copper at 2980 tonnes, silver at 10 tonnes and diamond at 112670 carats. Business Monitor International (BMI) forecasts average annual growth in the mining sector of 7.7 per cent between 2013 and 2015.