Marquise opal and diamond ring

Old marquise ring in 18Kt yellow gold and silver (hallmark: eagle's head), the center of which is decorated with an opal cabochon weighing approximately 0.70Ct in an entourage of rose-cut diamonds. Total weight of diamonds estimated at approximately 0.30 Ct. French work from the 19th Century. Gross weight: 4.30g Pattern height: 2.10 cm Finger size: 56 1/2 (diameter 18.00 / US 7.25). Condition: slight wear to the setting, very light micro scratches and oxidation on the gold and platinum parts, and some chipped diamonds, see photos. Opal is a stone that must be taken care of, the latter being mainly composed of water, it is very sensitive to large humidity variations. You will therefore need to avoid subjecting it to high heat, leaving it near a cotton pad (which could dry it out), or leaving it in a liquid for a long time. All our old rings.