Omegas Solid Gold Necklaces

The core. A springy wire or fine cable runs the full length of the chain, and every plate is threaded onto it through a channel or lugs on the plate's inner face. The plates are pushed up tight against one another and the ends of the core are fixed into the caps that carry the clasp.

There is no solder between the plates and no link joining one to the next. They are held in line by the core running through them and by the pressure of their neighbours, which is why the chain flexes smoothly and why a plate cannot be removed without dismantling an end.

This is also why an omega cannot tangle. There is nothing to loop through anything else; the whole chain is a single sprung band with a gold surface.

Because the core is set to a curve and wants to keep it. A chain of links has no shape of its own and simply hangs; an omega has a shape built in, and around the neck it holds that shape, resting on the collarbones at the front and clearing the skin slightly at the sides.

The effect is that of a collar rather than a necklace. The chain does not fall to the lowest point, does not swing as the wearer moves, and sits at the same place all day.

How far it stands off depends on the width and the curve set into the core. A fine round omega follows the neck fairly closely; a wide flat one sits as a distinct arc across the upper chest.

The shape of the plate. A round omega is built from plates curled into a full tube, so the chain is circular in section, like a smooth rigid cord, and its highlight is a single line along the crest.

A flat omega is built from plates pressed into a low arch, so the chain is wide and shallow, lies flat against the chest, and reflects as a broad band. Flat profiles are generally wider than round ones.

The construction and the sprung core are the same in both. What changes is the profile, and therefore which slide pendants and enhancers will fit: a slide made for a flat omega will not pass over a round one, and the reverse.

Usually not. The bail on an ordinary pendant is small and round, sized to pass over a linked chain, and it will not go over the profile of an omega without forcing. Forcing it scores the plates and can push them out of line.

Even where a bail is large enough, an ordinary pendant is designed to hang and swing, and an omega does not give it anything to swing from. It sits stiffly against the chain and tends to twist to one side.

The right fitting is a slide pendant, built with a wide smooth bail that matches the omega's profile, or an enhancer with a hinged bail that clips around the chain. Both rest on the chain properly and stay where they are placed.

On it, rather than from it. The slide's bail is a smooth tube or arch shaped to the omega's profile, and it passes over the chain and rests there with the plates undisturbed. Because the chain does not move, the slide stays wherever it is positioned.

A well-fitted slide moves along the chain with gentle pressure and stays put otherwise. Too tight and it scores the polished surface as it goes on; too loose and it rocks as the wearer moves and marks the plates beneath it over time.

Slides and enhancers are made for a specific profile and width, and the listing for each states which omega it suits. A slide for a wide flat omega will not sit correctly on a narrow round one, whatever the metal.

Because they cannot be adjusted the way a linked chain can. There is no link to add or remove. The plates are threaded on a continuous core fixed into caps at either end, and changing the length means dismantling one end and rebuilding it.

Manufacturers therefore produce omega chains in a small number of standard lengths and finish each one complete, with the core tensioned and the caps fixed. The chain is sold as a finished collar rather than as a length of chain to be cut.

The practical consequence is that the length has to be right at purchase. An omega sits as an arc rather than hanging, so the length decides where on the chest that arc rests, and that is not something to guess at.

It can, by a jeweller who is familiar with the construction, but it is a rebuild rather than an adjustment. One end cap is removed, plates are slid off the core, the core is cut, and the cap is refitted with the core under tension.

If the core is not refixed properly the plates nearest the cap lose their pressure against one another and begin to rattle, and the arc softens at that end. It is a job for a bench that has done it before rather than for a general chain repair.

Lengthening is not practical. The core is continuous and a join in it would not hold the curve, so an omega that is too short is better exchanged than altered.

Flat, in its own natural arc, in a box wide enough to take it without bending. An omega laid in the shape it wants to hold is under no strain at all and can be stored that way indefinitely.

It should never be coiled, folded, or pressed into a pouch. Bending the chain tighter than its set curve strains the core, and bending it against the curve or twisting it forces the plates apart and can put a permanent kink into the wire beneath them.

Nothing should rest on top of it. A weight on a stored omega presses the plates and can flatten a round profile or dent the edges of a flat one, and unlike a linked chain the surface has nowhere to hide a mark.

Bent gently within its own curve, nothing; the core is designed to flex that far and springs back. Bent sharply, or against the direction of its curve, the core takes a set, and the chain no longer returns to a smooth arc but holds an angle at that point.

The plates either side of the bend are pushed apart on the outside of the angle and crowded on the inside, which shows as a gap or a step in the mirror surface. On a flat omega the edges of the plates can lift.

A jeweller can sometimes ease a mild kink out of the core and reseat the plates, but a sharp bend is usually permanent. Prevention is simple: the chain is put on and taken off open, never pulled over the head, and stored flat.

Nearly always a box clasp built into the end caps, with a hinged safety catch. The caps that fix the ends of the core are made to the same profile as the chain, so the closed clasp continues the line of the collar and reads as part of it.

A box clasp suits an omega because the chain has to be opened fully and laid around the neck; there is no pulling it over the head. The tongue pushes into the opposite cap and locks, and the safety catch folds over to hold the two caps together.

Some omega chains are finished with a bayonet or a push-in barrel that is nearly invisible when closed. Whatever the fitting, it is the one rigid point on the chain and the plates beside it carry extra strain, so it is worth checking for looseness from time to time.