This specific and unusual ring is a 0.85 CT Rose Cut Diamond and 1 CT Black Opal in a Mid Century Modern surround in 14 K gold. The ring is size 6.5 and weighs 12.4 grams. The face is 3/4" by 7/16" and has been hand made from Scandinavia.
The fine ring is hallmarked 585 for 14 K gold and has an inscription Julien 1963 which dates it perfectly. The Diamond is eye clean VSI and 'H-I' for color. The deeply blue Opal is a doublet but has amazing sheen.
This substantial ring could be worn equally well by either gender and could be sized by your local Jeweler if needed.