A phenomenal Edwardian platinum, diamond and amethyst bow brooch by Cartier. Four tromp l'oeil amethyst loops, each surrounded in old European cut diamonds, flank a center 1.08 carat, J/K, VS2 old European cut diamond.
Each of the double loops of the bow appears to be set with two amethysts, but there is in fact only one amethyst on each side. The gemstones are precision-cut to fit perfectly into the platinum setting and give the appearance of being four stones. The amethysts are graded as medium, moderately strong Purple (P5/4) in color, with eye-clean clarity. This is the color and intensity sometimes termed "Siberian".
The 104 old mine cut and rose cut diamonds along the platinum borders total approximately 2.94 carats range from VS2 to SI2 clarity and H-J color.
The platinum setting is beautifully crafted, with a pierced gallery and engraved details around the collet setting of the center stone.
The brooch is hallmarked with the extremely rare master goldsmith's mark used by Cartier for only a three-year period, 1919-1922.
Origin: Paris, France, 1919-1922. Condition: very good, there is a small chip on the inside edge of each amethyst near the junction with the center diamond, visible upon very close inspection in strong raking light (one visible only from the reverse). Size: 3" x 27/32". Weight: 18.7 grams. Approximate Total Gemstone Weight: amethyst, 22.68 carats; diamond, 4.02 carats.