It certainly has the appearance of an Omega Sapphette. I’d guess early to mid 1960s. These were only made in 14 and 18 karat gold cases. The gold alloy depending on the country that the watch was retailed in. Manual wind. My spouse has several Sapphettes. The glass is a synthetic sapphire, facetted in the same manner that gemstones are faceted. Your wife shows excellent taste!