This is a beautiful antique Victorian lavalier or pendant made in 9K rose gold and set with two turquoise cabochons. It is marked S Bros and 9K gold on the back. The pendant was made by Sydenham Brothers. They were located in Birmingham, England and were in operation through the later part of the 19th and early part of the 20th century. An advertisement from 1913 describes them as makers of diamond and gem set jewelry.
It measures about 1 1/2 inches by about 3/4 inches and it is in very good condition.