Stone setting types, and what each one asks of the CAD file

Every setting type makes a different demand on the model. Some need metal above the girdle, some need a seat and nothing else, and some need a wall thickness that will not collapse when the setter starts cutting. Getting that right in CAD is what separates a file a setter can work with from one that gets sent back.

Prong, or claw

The most common setting and the most forgiving. Three to eight prongs rise from a head or basket and are pushed over the girdle of the stone.

In the file it needs prongs thick enough to survive casting and still have material to work with after the setter files them down — much below 0.8mm at the tip and you are asking for trouble. It also needs a seat cut, or at least a clear indication of where the girdle sits.

Best for maximum light into the stone and for anything where the client wants height. Worst for catching on clothing.

Bezel

A continuous wall of metal wrapped around the stone, pushed over the girdle to hold it.

The wall needs enough thickness to be burnished over without tearing, and a clean internal seat for the stone to sit on. A bezel modelled too thin will not survive setting; one modelled too thick cannot be pushed over at all.

Best for durability and for softer or more fragile stones. Worst for brilliance, because the wall shades the stone from the side.

Half bezel, or partial bezel

Two arcs of metal rather than a full wall, leaving the sides of the stone open. It behaves like a bezel where it touches and like nothing at all where it does not, which makes it a useful compromise when a client wants security without losing all the light.

Pavé

Small stones set close together in a field of metal, held by tiny beads raised from the surface between them.

This is the setting most sensitive to the file. Hole spacing, hole depth and the amount of metal left between stones all have to be right, because the setter is raising beads from material that has to be there. Too little metal between holes and there is nothing to raise; too much and the field looks clumsy.

Channel

Stones sit in a groove between two parallel walls, with no metal between them. The walls are worked over the girdles to hold the row.

The file needs the channel width matched to the stone diameter and the seat depth consistent along the run, or the row will not sit level. Calibrated stones matter more here than in almost any other setting.

Flush, or gypsy

The stone is set into a hole in the metal so its table sits level with the surface, held by metal burnished down around the rim.

It needs a decent thickness of metal to sink the stone into — this is not a setting for a thin band — and a hole modelled to the right depth. Very durable, and popular for men's pieces for that reason.

Tension and bar

Tension settings hold a stone by the spring pressure of the metal itself; bar settings hold a row of stones between short bars rather than continuous walls.

Tension in particular is not a setting to design casually. It depends on the elasticity of the finished metal, and it needs discussion with whoever is making it before the model is finalised.

Choosing between them

The decision usually comes down to three things: how much light the client wants into the stone, how much wear the piece will take, and how much metal the design can afford.

• Maximum brilliance, formal wear: prong.
• Everyday wear, active hands, softer stones: bezel or flush.
• Rows and fields of small stones: pavé or channel, depending on whether you want visible metal between them.
• A compromise on a solitaire: half bezel.

Tell us the setting before we model it

The setting type is not a finishing detail — it changes the geometry from the start. A head modelled for prongs cannot be turned into a bezel without rebuilding it, and a pavé field laid out for 1.3mm stones does not accept 1.5mm ones.

Send the setting type with the brief and the stone sizes if you have them. Quotations are free, and getting this right at the file stage costs nothing compared with fixing it at the bench.