This is a wonderful design by ADOLPH KATZ of CORO, INC. It is signed CORO in script on the back. It is designed in guilded brass -- at the top is a oval turquoise cabachon and 4 rhinestones -- below that is a round turquoise cabachon surrounded by rhinestones -- below that is a simulated emerald square cut rhinestone and at the bottom is another round turquoise stone. The knocker actually moves up and down just like a real one -- on the knocker at the bottom center is a sky blue rhinestone. This Doorknocker is described in Maryanne Dolan's book COLLECTING RHINESTONE & COLORED JEWELRY Fourth Edition, on Page 243. The condition of this piece is very good.