Liquid Rock Concrete. Measuring 8 feet long and 9 inches thick, this concrete sink weighs 800 pounds. Integrated stainless steel grates serve a decorative function, and they also can be used as countertop surfaces. Another unique design by this fabricator is a countertop in which sand and rock are laid inside to create a Zen garden feel, and then topped with glass. 541-610-2271. www.liquidrock.biz.