Isolated from radioactive water spring C1 (30 l/min., 29 deg C, 11 kBq/l) springing up at a depth of 500 m below the surface of gneiss mountain bedrock, in the former silver-uranium mine Svornost (Jachymov, Czech Republic; GPS 50 def 22 min 22.9 sec N 12 deg 54 min 42.1 sec E).