A group of tourmaline, diamond and colored sapphire "étoile de mer" brooches, by René Boivin. Photo Christie's Image Ltd 2014

Comprising five brooches, each brooch enhanced with pink cabochon tourmalines, to the circular-cut diamond, sapphire, purple, pink and violet sapphire starfish, mounted in 18k white or 18k blackened gold, 2005, with French assay marks and maker's marks. Each signed René Boivin, nos. 1/1, 2005. Estimate $20,000 – $30,000

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