This men's signet ring with black onyx pairs a classic, masculine form with a stone of deep, matte black. The onyx is cut as a cabochon, so light doesn't scatter across facets but glides across the smooth surface in one calm reflection, visible with every turn of the hand. Craftsmen have long linked this stone with strength, endurance and confidence - an association this signet carries through its plain, understated form, free of unnecessary ornament.

We assess the stone before it's even set, looking at the depth of black and the absence of discolouration - only pure, even-toned onyx makes it into the signet. Silver and good stones are rising in price, and onyx with this depth of colour is harder to find today, which makes this purchase worth making now. The signet is made of refined European silver, and the 925 fineness confirms the purity of this alloy - free of nickel and other additives that could irritate the skin on the hand. A layer of rhodium adds hardness to the metal and protects the surface against scratching and tarnishing, so the shine stays clear for a long time. The signet is signed with the French maker's mark registered at the assay office, which attests to the origin of the metal.

A signet like this sits well on the hand with a light shirt and a rolled-up sleeve, or a linen jacket in a natural shade - the black of the onyx acts here as a calm, masculine accent without excess. It also suits a simple watch on a leather strap and classic trousers in a muted colour. At 5.5 g, it feels substantial without getting in the way of everyday gestures, like holding a cup or fastening a shirt cuff. The cabochon onyx remains the main focal point, around which the whole simple form of the signet is built.