An Opal and Diamond cluster ringA lovely ring which has been hallmarked in Sheffield (no date letter), featuring an opal doublet as the principal stone. The opal is oval cabochon cut, measuring approximately 8. 0 6. 0 mm, with a good spread of colour and set in a rim (rub over) setting. Surrounding the opal are twelve round brilliant cut diamonds, each approximately 2. 0 mm in diameter, with a total estimated diamond weight of 0. 35 carats. Diamond quality is assessed as colour IJ,