Folk term for a Celtic gold coin shaped like a small cup. According to folk belief RCs could be found where a rainbow touched the earth. RCs, which could often be found in ploughed fields after heavy rainfall, were thought to bring luck and had many different effects ascribed to them.
On the obverse RCs have an abstract head or a smooth bump, sometimes a star, a hand, writing, an ornament, a cross or a bird's head. The reverse is concave, often with a representation of a torque (Torques) with spheres in it. It is esp. the Celtic tribes of southern Germany and the Boii who are credit…