It's always a good idea to have a conversation with your jeweler about how their jewelry is made whenever you're making a big-ticket purchase. One important distinction to make is to determine whether the piece was hand-fabricated or cast from a mold.
The technique of hand-fabrication dates back to antiquity and serves as the basis of all jewelry manufacturing. It consists of working from certain primitive metal forms as wire and sheet, and forming it to the desired shape using techniques such as hammering, bending, filing, sawing, and soldering.
Casting also has a long and storied history, and consists of pouring molten metal into a hollow cavity that's shaped like the piece you'd like to create. The metal flows into the mold and then freezes to its final shape, and is then finished to achieve a smooth surface.
Types of Casting
Casting generally falls into two categories: single-use casting and reproducible casting.
In single-use casting, a jeweler will craft a piece in some medium, for example wax, and then form a one-time-use mold around that piece in some type of casting plaster. The wax can then be melted out simply by heating the mold, and molten metal can be poured to fill the now-empty cavity. The mold is then generally destroyed to remove the piece. When using wax, this technique is called lost wax casting.
The modern demands on the jewelry industry are leading many jewelers to take shortcuts in crafting their jewelry, and many jewelers now depend on reproducible casting for their production runs.
In a reproducible casting process, typically a piece will be fabricated by hand using traditional techniques or formed in wax, and then the mold-making will be outsourced to an outside casting house that specializes in making permanent molds. These molds can then be reused to produce numerous nearly identical pieces of jewelry.
Growing in popularity with the advent of 3D printing technology is the process of designing jewelry on a computer, and then transferring it to a 3D printed medium, such as wax, for the purpose of forming a mold. Using this technique, jewelers can produce complex geometries that would be massively difficult using older techniques. However, it also has a tendency to create dry, logical pieces that lack a sense of human soul, in my opinion (and I'm a computer programmer by day!)
Casting jewelry from wax allows jewelers to create certain forms that would be particularly difficult to achieve using hand-fabrication methods. Working in wax is more similar to carving, and so it can ultimately achieve some great results. One distinct advantage, when setting stones, is that it is possible to embed the stone directly in the wax to make sure you get a perfect fit!
Reproducible casts can dramatically reduce the cost and naturally improve the reproducibility of jewelry manufacturing. Casting is often outsourced to specialized casting houses that do nothing but casting using lower-skill, lower-wage labor. Depending on the scale of the run, the pieces can then either be finished in a factory setting or a more bespoke bench setting.
There are, however, some major drawbacks to using castings. When pouring molten metal, the metal might flow differently through differently sized cavities in the mold. It is possible for air bubbles to form in certain areas, for the metal to be thinned in certain areas, and generally the density of the metal is lower than that of fabricated pieces. This can lead to weak spots in the final product that are difficult to predict, detect, or control.
When manufacturing reproducible castings, most of the work is often performed by disinterested low-wage laborers. In addition to the higher probability of unfair labor practices, these laborers are sufficiently disconnected from the person who will eventually wear the jewelry, that they simply aren't likely to pay sufficient attention to finishing the product. This can cause them to miss flaws, and to generally take shortcuts in the interest of moving more quickly.
Even when finished by a more experienced jeweler to a high level of quality, the mass-production of jewelry through reproducible casts means that the pieces will never be one-of-a-kind. It means that there will be people out there with nearly identical pieces, to very tight tolerances.
There are plenty of jewelers out there who claim their pieces are hand-made, when in fact, they are outsourced to casting houses. The only thing they do by hand is to set stones and finish the product.
Be sure to ask your jeweler how they manufacture their pieces. It's generally best to find a jeweler who will either fabricate or cast from carved wax, though that may come at a cost premium.
For millennia, the manufacture of jewelry was dominated by skilled artisans with years of training who would spend days or even weeks on a single piece, focusing on every single detail to achieve a one-of-a-kind, magnificent work.
The introduction of mass production to the jewelry industry introduced numerous new techniques in both casting and hand fabrication that allowed jewelers to increase the rate at which they were able to produce pieces, which had the natural benefit of reducing the price tag and making jewelry available to more people.
Hand-fabricated jewelry consists of working from certain primitive metal materials, namely wire and sheet. At my studio, I alloy my own casting grain into ingots, which I then roll into these elemental pieces. Milling your own raw materials ensures that you get a high degree of quality, because you can pay close attention to its production.
There are two main types of deformations that can be performed on these raw materials, chip forming and plastic deformation.
Plastic deformation takes advantage of the malleability and ductility of metal to stretch and compress the metal in strategic ways to achieve a desired shape. This often consists of hammering, bending, rolling, and twisting. In general, the amount of metal is conserved through plastic deformation.
Chip forming leverages the forces of friction to remove metal and shape the final piece. This includes activities such as sanding, filing, sawing, drilling, and polishing. Chip forming ultimately leads to pieces of metal being removed from the final piece, reducing its weight in precious metals.
While these filings can be recovered by refiners and sawn-off chunks can be melted down for future pieces, it's important to minimize the amount of chip-forming where possible to waste as little metal as you can.
Because hand-fabrication requires intense concentration on the individual components of the piece, it has a tendency to produce a higher-quality result. That being said, it does require a higher level of skill on behalf of the craftsman. This higher quality comes at a higher cost.
Elemental pieces can be joined together using solder, a special alloy of metal that has a lower melting temperature, and can be melted to connect two other pieces of metal. The bonds formed by solder can be incredibly sturdy, since they typically consist of a nearly identical metal to the piece itself. However, these joints can sometimes represent weaker points on the final piece, and under extreme conditions, this could lead to cracks.
The process of plastic formation has some major benefits to the structural integrity of the piece. The crystalline structure of the metal is compressed and stretched and by using heat, it is reflowed to reach a more consistent density. Any air bubbles or weak spots formed during the casting of the ingots are eliminated through this process, producing an end result that tends to be much stronger, more consistent, and of a higher density.
When setting stones, casting can prove incredibly difficult for all but the most uniformly cut gems. Setting unusually shaped, asymmetric gems like the natural rough gems I use, can be nearly impossible to do with reproducible casts. It forces you to source a stone that fits your pieces, rather than crafting a piece that fits your stone.
Which should you look for?
Despite the slight risks associated with solder joints, fabricated pieces tend to last much longer than cast pieces. Cast pieces, unless hand-made by a highly skilled jeweler, rarely survive to become heirloom pieces.
The more important thing is how much attention your jeweler is able to pay to your particular piece. More attention by a skilled craftsman will generally lead to a better result, regardless of the techniques used.
I recommend speaking with your jeweler to get a good sense for how much attention they can pay to their work and where they source their raw materials. It's a major red flag to be dealing with a disinterested salesperson who can't tell you how the piece is made. That's likely a mass-produced piece of lower quality.
I hand-fabricate most of my pieces, and I think it tends to lead to a better result. I do sometimes use one-of-a-kind wax casts in sand or plaster to achieve a particular result that would be impossible (or just very difficult) to fabricate. I do not, however, do any reproducible casting. All of my pieces are truly handmade to order.
I can work with you to build something completely custom and one-of-a-kind, and I can walk you through the entire sourcing and manufacture process.