Theodor Fahrner Silver & Amethyst Brooch Art Deco (1920-1935). Theodor Fahrner jewellery is always well designed. It was made in Pfortzheim in the Black Forrest, Germany, and exported worlwide. It is highly collectable as it is good quality, and well documented in reference books of the period. This is a good looking amethyst, marcasite and silver brooch which is signed on the reverse.