Sterling Ouma Badge

Another find from a charity shop. Ouma, is Afrikaans for grandmother. I am not sure what the markings on this piece may represent. I would like to know if it is South African, who made it and when it was made.

I look for this a long time ago.

Found out that the U has a lion head in it and it was used as sterling mark for the Union of South Africa. The sterling mark were later replace by a Springbok head when it turned into a Republic.