A pair of diamond and sapphire scroll earrings by Rubel Frères, c.1935, each with nine curved branches, set with baguette-shaped diamonds and terminating with an invisibly-set oval-shaped sapphire, the hinged clips with baguette-shaped diamond semi circles with circular-cut diamond borders, French platinum control marks, partially obscured maker's mark in lozenge RFrs.. 29.9g, 4.2cm
For a similar pair of earrings by Van Cleef and Arpels see Van Cleef Arpels: The Art of High Jewellery (Paris: Les Arts Décoratifs, 2012), p. 106.
John and his brother Robert opened a workshop on Rue Vivienne in Paris, 1915. The Rubel Frères were producing jewellery that soon caught the eye of the great jewellery houses, such as Van Cleef & Arpels. The quality of their workmanship for the great houses was recognised to the extent that they were allowed to sign some of their pieces with their own maker's mark RFrs.
With the outbreak of the war, the brothers followed Van Cleef & Arpels to New York in 1939. They instantly took to the lavish night life. Tradition holds that whilst at the El Chico club, John sketched a flamenco dancer that developed into the first iconic Van Cleef & Arpels ballerina brooches. However, when the rights to produce these pieces could not be agreed, the rift that ensued between the brothers and Van Cleef & Arpels was irreparable.
'Mystery Set' refers to the unique technique associated with Van Cleef & Arpels, which they patented in 1933. The mystery is how rows of gemstones could be so perfectly set whilst no metal to hold them in place could be seen; no claws, collets or mounts were visible. The free-standing illusion is formed by a delicate lattice of rails slotting into grooves cut into the pavilion of each calibré-cut gemstone. The process takes hundreds of hours and could only be undertaken by a very small number of jewellers. Similarly set jewellery by anyone but Van Cleef & Arpels is referred to as 'invisibly-set'. The oval-shaped sapphires in lot 1409 are invisibly-set. Mystery-set pieces are extremely rare. Rarer still are invisibly-set oval stones. The sapphires in lot 1409 slot into the collet rather than a neighbouring stone, as with typical invisible settings, and use screws to their reverse enabling no fittings to be visible when worn.