Georg Jensen modernist Concave ear studs #136 D (Nanna Ditzel).

This pair of earrings typify the streamlined modernist oeuvre of Nanna Ditzel, designer to Georg Jensen in the mid-late 1900s. They bare post-1945 GJ hallmarks, 925 S Denmark, and the design number #136D.
They are most likely from the 60s/70s.