成人自拍视频A large-diameter diamond saw cuts a block of marble into dimension stone at a factory. Slabs and blocks of marble are used for stair treads, floor tiles, facing stone, cemetery stones, window sills, ashlars, sculptures, benches, paving stones and many other uses. Photo copyright iStockphoto / maskpro.
成人自拍视频Some marble is heated in a kiln to drive off the carbon dioxide that is contained within the calcite. What remains after kiln treatment is the calcium oxide - known as "lime." Lime is used as an agricultural soil treatment to reduce the acidity in soil. When applied in combination with fertilizer, it can increase the yield of a soil. This test plot shows a portion of a corn field where no lime and no fertilizer were applied. The plants in that plot are struggling to survive. Photo by the Agricultural Research Service, United States Department of Agriculture.