The millesimal value of 750 on Gold, which corresponds to the 18K, was used primarily by department stores in the USA - ca early to mid 20th C. The Bracelet was probably made by Manufacturing Jewelers and distributed by John Wanamaker that later became Macys. Although most of Macys marks usually show an Eagle, the Gazelle could have been a vintage hallmark used by the original maker, who unfortunately we cannot identify.
Hard to tell on the style of link although it does have a Greco-Roman appearance and very 1940s to 1960s.
