Dick Ravelli & Co. Sierkunst Atelier (Leiden 1943 – Valkenburg 1977). Founded by Dick and Jaap Ravelli in Leiden. In 1947, the company moved to Valkenburg. Jaap Ravelli used mainly black-baked clay. In the fifties many arts and crafts and floristry items followed in the typical 1950s style. In 1977, the bankruptcy followed by excessive competition from abroad.