This is an unusual color scheme for the Victorians, who usually chose bold contrasts over subtle harmonies. At first glance the three purplish stones seem similar, but on closer inspection, notice the nuance: a velvety amethyst, a fiery pyrope garnet, and a deep almandine garnet. Oh, and a rose cut diamond for good measure: the Victorians' favorite for catching candlelight.
The multiple independent rings joined at the back was a thing back then: they called it a "harem" ring. It was influenced by Western Europe's romanticized fascination with Ottoman culture, but likely had little similarities to anything worn in Turkey. It was more a projection of what Victorian England imagined as "exotic". Recommended reading: "Turquerie, an Eighteenth Century European Fantasy".
MATERIALS: 10k gold (tests), 2.8 x 2.3mm amethyst, 2.8 x 2.3mm pyrope garnet, 3.5 x 2.8mm almandine garnet, 2.5 x 2.2mm rose cut diamond
AGE: c. 1880
CONDITION: Very good - minor surface wear commensurate with age and use
SIZE: 5.25, cannot be resized; 8.2mm head, 3.8mm shank