This fast-drying, easy-to-mix reinforced cement is for use with indoor mosaic glass projects, such as furniture, boxes, frames, coasters, and more. This specially designed cement is stronger and smoother than grout. Dries within one hour. - Mosaic Stone Cement - 20 lb, IndoorMosaic Stone Cement, 20LB INDOOR - No mess, no hassle, just beautiful results. Mosaic Stone Cement is specially designed for use with mosaic glass projects. It's extremely strong (rubber cement will crack in shallow mosaic forms), and dries within one hour to a smooth, white finish.