Shandong abounds in mineral resources. More than 90 kinds of minerals have been verified or are being mined, including coal, petroleum, natural gas, iron, copper , aluminium, diamond and magnetite. The province has large deposits of gold: eastern Shandong's gold production ranks first in China. Shandong is also rich in non- metallic ores, such as graphite, marble, granite, gypsum, sulphur and talc. The province is one of the four largest salt production bases in China. With a 3,200 kilometre- long coastline, one- sixth of China's total, Shandong has a strong fishing and aquaculture industry. The province is the country's largest exporter of marine products such as prawns, crabs, scallops, shellfish, algae, abalone, sea cucumbers and sea urchins.