An Edwardian colour-change sapphire and diamond cluster ring

An Edwardian colour-change sapphire and diamond cluster ring, the cushion-shaped sapphire weighs approximately 6.00cts, set within a surround of graduated old circular-cut diamonds, with pierced and carved scroll decoration to the gallery in platinum, size K 1/2

Accompanied by report number 18209 dated 20 December 2019 from The Gem & Pearl Lab London stating that the cushion-shaped sapphire measures 13.50 x 10.80 x 4.10mm and is a natural colour change sapphire, exhibiting purple-ish blue colour in daylight and purple in incandescent light, with no indications of heat treatment. Origin: Sri Lanka (Ceylon)