I'm not particularly fond of amethysts, but a piece I adore – and a perfect match for its strong-willed and charismatic wearer – is the Duchess of Windsor's amethyst and turquoise bib necklace, a special order from Cartier Paris in 1947: one heart-shaped faceted amethyst, twenty-seven emerald-cut amethysts, one oval faceted amethyst, turquoise cabochons, twisted 18 and 20 ct gold, platinum, brilliant- and baguette-cut diamonds.