Roselane Antiques has dated this piece to the 1960s.
It is sitting slightly raised above the outer diamond halo.

The diamond halo surrounding the central stone displays twelve contrasting lively diamonds held within a gently curved outer edge.
Sapphire approx: 2.30ct
Diamonds approx: 0.88ct
Colour H-I
Clarity: S1
Size: O
Weight: 4.8gms
Roselane Antiques has dated this piece to the 1960s.
You can view the stock and full dealer information on the Roselane Antiques Profile Page