A kidney wire is an earring fitting in which a single piece of wire is bent into an asymmetric loop, passes through the pierced earlobe, and closes when the free end is hooked into a small notch or eye on the front portion of the wire. The shape of the closed loop, vaguely reminiscent of a kidney bean in profile, gives the fitting its name.

Construction and use

The wire is typically formed from gold, silver, or surgical-grade stainless steel, drawn to a diameter between 0.7 and 1 millimetre. The front portion of the wire descends in front of the ear and supports the dropped element of the earring, whether a charm, drop, or small dangle. The back portion curves up behind the ear and engages a notch on the front near the ear lobe, closing the loop. The wire is springy enough to hold its closed position under the gentle resistance of the ear.

Position in the trade

The kidney wire sits between the simple shepherd's hook, also called a French wire, and the more secure leverback. It is more secure than a shepherd's hook because the closed loop cannot fall out under normal movement, and it is simpler and lighter than a leverback. It is used for earrings of moderate weight, typically with drops up to several centimetres, and is favoured for designs where the curve of the wire itself is part of the visible composition. Kidney wires are not generally used for very heavy earrings, where a leverback or post-and-omega-back gives more security and weight transfer.

Variants

Variants include kidney wires with safety bumps, additional security catches, or decorative elements worked into the wire. Some makers produce kidney wires in textured, twisted, or hammered finishes for visual interest. The wire can be made in a wide range of metals and is one of the standard options offered by jewellery findings suppliers.