DIAMOND BROOCH Two triangular-cut diamonds — French craftsmanship, Auguste Leroy...

DIAMOND BROOCH
Two triangular-cut diamonds — French craftsmanship, Auguste Leroy
An elongated hexagonal brooch with Art Deco-style geometric decoration, crafted in 18-karat gold (750 ‰) and platinum. It is set at both ends with two large old-cut triangular diamonds, their points facing each other on either side of a central X-shaped motif: one a “fancy” brown diamond weighing 13.67 carats, the other a G-color diamond weighing 4.57 carats. The openwork setting is entirely pavé-set with old-cut and eight-eight-cut diamonds, forming a pattern of lines and triangles accented with millegrain detailing. The brooch is equipped with two retractable loops, allowing it to be worn as a pendant as well. The two diamonds may be reused stones, for which the setting was specially crafted. The brooch mechanism was added at a later date.
French work, circa 1925–1930. Eagle-head hallmark; master goldsmith’s mark of Auguste Leroy (active in Paris from 1912 to 1935).
Height: 2.75 cm — Width: 4.57 cm — Gross weight: 18.44 g.
The diamonds:
— an old triangular-cut diamond, 13.67 ct, “fancy” brown color, SI2 clarity, no fluorescence, Type IIa diamond, no indication of treatment;
— an old triangular-cut diamond, 4.57 ct, color G, clarity SI1, no fluorescence, Type IIa diamond, with significant chips, no indication of treatment. Condition: scratches. Accompanied by two reports from the French Gemmological Laboratory, Nos. 426403 and 426404, dated June 15, 2026.