The mining and processing sector's share of GDP in 2000 was 1.5%, down from 3.7% in 1993. Mining and processing of industrial minerals and the production of construction materials continued to be of regional and domestic importance. Economic resources of most metals have been depleted; at year end 2000 gold-bearing and tin-tungsten ores were among the exceptions. All the raw materials consumed by the country's steel industry were imported, including iron ore and concentrate, manganese ore, copper, and unwrought lead and zinc. Lead and zinc have not been mined for at least six years, and the number of registered deposits declined from 27 in 1995 to 11 in 2000—none was under exploitation during the period. The country's eight iron ore deposits were no longer worked. In 2000, kaolin production was 5.57 million tons, up from 3.05 million tons in 1998; common clays, 1.1 million tons, up from 759,000 in 1997; common sand and gravel, 12.6 million cu m, up from 9.3 million in 1998; foundry sand, 829,000 tons, compared to 717,000 in 1999 and 1.08 million tons in 1996; glass sand, 985,000 tons, compared to 827,000 in 1998 and 1.1 million tons in 1996; dimension stone, 320 million cu m, up from 190 million in 1996; limestone and calcareous stones, 11.8 million tons; building stone, 10.1 million tons; hydrated lime and quicklime, 1.2 million tons; feldspar, 337,000 tons, up from 244,000 in 1999; diatomite, 34,000 tons, down from 42,000 in 1997; and graphite, 23,000 tons, down from 30,000 in 1996. Output of crude gypsum and anhydrite went from 443,000 in 1996 to 82,000 in 2000. The Czech Republic also produced arsenic, hydraulic cement, bentonite, dolomite, crude gemstones and pyrope-bearing rock, illite, iron ore, nitrogen, quartz, salt, basalt (for casting), silver, sodium compounds, sulfuric acid, talc, uranium, wollastonite, and zeolites.