The deep purple of the amethyst in this ring shifts shade with every movement of the hand - from dark purple to a lighter, clearer tone. The cabochon cut doesn't break light into small sparkles, but rounds it into one calm glow that settles over the stone like a faint mist. The signet form, smooth and compact, gives the whole piece a classic, slightly masculine character, though it sits just as well on a woman's hand. In old jewellery tradition amethyst was associated with calm and clarity of thought - that association still lingers today, though here the stone is above all a pure, deep colour.

A piece like this - free of flaws, with an even, saturated colour - is easy to overlook and hard to match once it's gone. Silver and good coloured stones get more expensive year after year, so buying at this price makes sense today. The stone is set in refined European silver, sterling silver 925, rhodium-plated with a layer of rhodium that brings out the depth of the purple and protects the surface from tarnishing and scratches - the shine stays clear for a long time. The alloy contains no nickel, the metal most often responsible for skin reactions, so the ring can be worn without worry. The French maker's mark confirms the origin of the metal and is struck at the French assay office.

This signet ring feels at home in everyday, understated outfits: with a soft, chunky wool sweater, in a monochrome look built on greys or beiges where the amethyst's purple immediately draws the eye. It also works with a simple shirt and jeans - the classic signet form doesn't need a special occasion. At a medium size and weighing 2.9 grams, it sits lightly on the finger, with its purple remaining the focal point of the whole look.