This is an opal and diamond set cluster ring that has a four claw set, oval shaped, cabochon cut, white crystal opal.   The opal measures approx. 6.70mm x 5.85mm x 2.77mm deep and is claw set in white metal. The opal has been calculated to weigh 0.64ct.  It has a translucent body colour with a strong green/blue and minor red/orange play of colour.
 
There is a surround of alternating groups of claw set brilliant cut diamonds (20 in total and each diamond measuring between 2.00mm-2.30mm diameter) and baguette cut diamonds (four in total and each diamond measuring 4.00mm x 1.30mm). All of the diamonds are set in a three row raised cluster head that measures approx. 14.70mm x 14.60mm.  
The estimated weight of the brilliant cut diamonds is 0.72ct and the  colour and clarity have been assessed as H-J and VS2-SI2.  
The estimated weight of the baguette cut diamonds is 0.24ct and the colour and clarity have been assessed as G-H and VS-SI.  
 
The white metal band has been stamped with "18ct" and it tests as 18ct white gold. 
 
The age is assessed as circa mid-20th century.  The ring will fit finger size 7 (US/Canada), O (UK/Australia).  Some resizing possible which we would carry out in our own jewellery workshops.