Sand and gravel, used primarily for roadbuilding and general construction projects, rank fourth in value. Most of the sand and gravel is located along the Coastal Plain, especially in Henrico, Chesterfield, Prince George and Princess Anne Counties. Sand and gravel are also used for "fill," for engine sands, railroad ballast and glass. Clay (excluding that type used in the manufacture of pottery) ranks fifth in financial value. Clay deposits are widespread throughout Virginia--especially in Botetourt, Buckingham, Chesterfield, Henrico and Prince William Counties--and vary from red to light-colored to white. They are used chiefly for brick and tile construction. With respect to metals, Virginia mines the following: Barite--widespread deposits--used in the preparation of oil well drilling, muds, chemicals Diatomite--Tidewater section--an earthy material used as an insulator, as a filter medium for oils, in sugar refining Feldspar--widespread deposits--chiefly in Amelia, Bedford and Prince Edward Counties--used chiefly in the ceramics industry for making pottery and in the manufacture of glass, enamelware, enamel brick, and as an abrasive in soaps and cleansers Gold--northeast Piedmont and Blue Ridge Plateau--little gold at present but the best developed gold deposits are located in Fauquier, Buckingham, Culpeper, Goochland, Louisa, Orange, Spotsylvania and Stafford Counties--chief uses of gold include as a bullion for backing of United States currency, in the manufacture of jewelry, in the process of gilding, lettering, plating, and in the chemical industry Lead and Zinc--lead: in Albemarle, Spotsylvania, Louise and Wythe Counties--used in the manufacture of paint, in storage batteries, cable covering and as an alloy; zinc: in Scott, Wythe, Rockingham and Spotsylvania Counties--used for producing metallic zinc, for galvanizing and (when alloyed with copper) for making brass Mica--among the crystalline rocks of the Piedmont Provinces--white mica called muscovite is used chiefly for electric insulation, for coating wallpaper, for roofing paper, in lubricants and in heat-resistant windows; sheet mica is used in electronic equipment--in Amelia, Bedford, and Henrico Counties Natural gas--in Buchanan and Dickenson Counties--used for fuel and power Pyrite--widespread deposits, particularly in Carroll County--used for its sulphur content in the manufacture of sulfuric acid--Virginia ranks second in quantity Tungsten--in Mecklenburg County--used for making high-speed tool steel and munitions Wool-rock--in the Valley of Virginia and the Ridge provinces--used for the manufacture of rock wool for heat and sound insulation