Commercial production includes coal, dolomite, gypsum, and limestone. Common calcium-containing minerals are chalk, limestone, gypsum, and anhydrite. The mortar used was a mixture of gypsum, sand, pulverized limestone and water. Soil may contain iron sulfide as pyrite or calcium sulfate as gypsum. It consists of layers of gypsum and marl and limestone. Gypcrete is a mixture of gypsum plaster and fibreglass rovings. These calcite fins were once crack filling gypsum and anhydrite. Interior surfaces sometimes receive a final layer of gypsum plaster. Also cement board provides a stronger bond and support with tiles than typical gypsum board. Victoria also produces limited amounts of gypsum and kaolin. Chemically modified or unmodified starches are added to the stucco containing primarily gypsum. Roofing, Siding, Insulation, Gypsum and Ceilings. Gypsum and quicklime were used as binders. Other important minerals include silver, coal, gypsum, and sulphur. Some sands contain magnetite, chlorite, glauconite, or gypsum.