Here is an unusual one! The top of the specimen is a thin vein of baryte-calcite-quarts with crystal sections of wittichenite embedded in the baryte, mostly. The old German label also states there is klaprothite on the specimen. The granite matrix IS a a bit radioactive and there are some secondary minerals on the piece but I am not confident that any are klaprothite. Might be!
Interesting old timer! from the vicinity of the type locality for Wittichenite.