Marked Silica Diatite Patented Dec. 15, 1868 Norwalk Lock. Co. Found with rose patent #113,842,  December 10, 1873 also by H.H. Elwell.  Silica Diatite is the name of a composition of finely-powered silica and gum-shellac - patent #85018 Dec. 15, 1868 by J.M. Merrick. Click on each photo below to view additional images and information.