720 - An opal and diamond ring

An opal and diamond ring Gold Set with an opal and 20 brilliant-cut diamonds with an approximate weight of 1.50 ct. 20th century (mid) Unmarked, bearing only the goldsmith's mark of Raúl Ferreira & Mário (reg. 1943) Size: 5 (EU) 6.3 g VIDAL, Manuel Gonçalves; ALMEIDA, Fernando Moitinho de - "Marcas de Contrastes e Ourives Portugueses (século XV a 1887)". Lisbon: IN-CM, 1996, no. 758