Calcium Silicate Corporation's silica source (mostly CaSiO₃) is a byproduct of the production of elemental P reduction of phosphate rock with coke in electric arc furnaces. This source located the Tennessee valley area is the most pure, cost effective source of soluble silicon. It has been the predominant source of commercially available silicon since the company's conception in 1987. The finished product is commercially available in bulk and granulated enhanced forms. Annual sales exceed 120,000 tons per year.