A diamond and rock crystal ring, by René Boivin. Photo Christie's Image Ltd 2014

Designed as three sculpted rock crystal cylinders, enhanced with circular-cut diamonds, to the 18k white gold hoop, mounted in 18k white gold, with French assay mark and maker's mark, 2005. Signed René Boivin, nos. 1/1, 2005. Estimate $7,000 – $10,000

Christie's. MAGNIFICENT JEWELS, 16 April 2014, New York, Rockefeller Plaza -www.christies.com