An unusual Art Deco onyx, heliodor and diamond pendant, France, 1920s

An unusual Art Deco onyx, heliodor and diamond pendant, France, 1920s, centring on a circular-cut diamond weighing approximately 0.70 carats, within a hexagonal onyx setting and calibré-cut helidor border, to a pendant designed as a geometric openwork plaque with foliate details, set with circular-cut diamonds and crossed with lines of calibré-cut onyx, mounted in platinum, length 4.5cm, French assay mark for platinum, partial French maker's mark L with oak leaf/feather