This naturally occurring alloy is a blend of gold and silver, with occasional traces of other elements such as copper or platinum. Due to its origins, the amount of gold and silver in electrum varies, going from 20-80% gold and 20-80% silver. Electrum may be man-made, but this version is referred to as “green gold.”
Electrum was recorded by Pliny the Elder and used to decorate pyramids in ancient Egypt. The alloy’s most common use in the ancient world was as a currency, with Byzantium, Greek city states, Carthage and others using electrum coins. Other uses for the alloy included elaborate jewelry shaped into flowers faces, bells and animals. Examples of this ancient jewelry may be found in many museums, including the Louvre.
Japanese for “one quarter,” shibuichi is a copper/silver alloy often covered with a dark patina. Despite what the name implies, the proportions of copper to silver can span from 95%-70% copper, rather than being measured in increments of 25%. Depending on the recipe, gold may be added to the mix. The variations of recipes allows for a range of colors in the alloy.
Like shakudo, shibuichi was originally used for decorative sword fittings. When swords fell out of favor during the Meiji period, smiths turned to making jewelry and other luxury goods with shibuichi. It’s also used as a component in mokume-gane.
In jewelry, die striking is the act of compressing a piece of precious metal between one or two specially shaped blocks. Striking may be used in lieu of components cast from molds, though both methods are time consuming. The resulting jewelry findings are dense, leading some to believe that they are sturdier than pieces made by other means. Thousands of pounds of pressure are used in creating die struck jewelry.
Aside from making findings, die striking is also used to impress fanciful images in relief or negative space. Like a mold, die struck patterns have the advantage of being made in quantity with speed, rather than hand crafting repeats of the same item. The quality of a piece is also dependent on the quality of the die and its operator. A plate may last for years, or break from misuse. Some manufacturers may promote the density of die struck items as being strong due to its compression.
Etching is a chemical process which burns designs onto a piece of jewelry. Once a pattern is chosen, it’s inscribed in wax upon precious metal while leaving portions uncovered. The piece is then exposed to a strong acid or base. The chemicals eat away at the exposed metal, creating indents. When the acid and wax are washed away, the result is a picture of varying depths.
While etching is associated with printmaking and illustrations, it also is used in jewelry. It may be used in place of, or in addition to intaglio work. Etchings made for print work is subject to strain which causes even steel plates to wear with use. Jewelry etchings by contrast experience less stress, allowing them to be made from softer fine metals.
Derived from the Latin “filum” and “granum,” meaning thread and seed respectively, and shortened from the English “filigreen,” filigree is a delicate form of embellishment made of tiny beads or wires soldered together. The bits of metal are arranged in decorative patterns, giving an impression of lace. Etruscan and ancient Greek jewelry frequently used filigree, as does present day India.
Filigree can be made in a number of ways, such as sculpting wire, arranging beads on a metallic base, or creating a maze of delicate wires supported by a sturdier frame. Modern filigree is often made in the third style, to protect the fragile inner workings. With the help of a blow torch and binding medium, the filigree melts into place.
Named from the Latin word “granum,” meaning grain, granulation is a technique in which a pattern of tiny gold or silver balls adorn a piece of jewelry. It’s a subset of filigree that refers to balls 3 millimeters or smaller in diameter. Granulation goes back to at least 2000 BCE, found in Etruscan and Ur archaeological sites. Excavations in the 19th century revived interest in the art.
To make granulated jewelry, gold or silver alloys 18 karats or purer are used, due to the ease in which they melt and fuse with the base. The beads are made through careful cutting of thin metal sheets or narrow wire coils. The metal pieces are treated to turn them into round shapes and are sorted to make sure the grains are of uniform size. After arranging on the base of the jewelry, the pieces bond together with the help of solder, or heat alone.
Also known as embossing, repousse in jewelry design takes metal and creates a raised image. The term comes from French and Latin words meaning “to push up,” which in turn were inspired by how patterns are made by pressing tools against the reverse side of a thin sheet of metal. Embossing is similar, but is sometimes used only to refer to designs made by machinery. Images may be stylized, geometric, or depict animals and flowers.
Heat is often used to help soften metal and make it easier to mold. Tools are usually made of steel with hardened tips to aid with shaping. Saws, hammers, chisels, punches and torches are all used to make repousse. During the process, the metal must be treated from time to time to discourage breaking. The metal to be shaped is placed on a surface that will yield but not break from the constant blows. After the repousse, the piece may be further embellished with techniques like inlays or patinas.
Derived from the Latin word for “blackened,” niello is used to highlight designs in etched and engraved metal. By inlaying traces of black within the valleys of the design, the upper part of the pattern stands out. Ancient Egyptians are credited with discovering the technique, which spread to the Roman Empire and medieval Europe. Niello has also flourished in Thailand for centuries.
The substance that creates the blackened areas is usually an alloy of sulfide. Traditional mixtures were made of sulphur, silver and lead, while modern versions add copper, borax and occasionally antimony. The pasty mixture is applied to the jewel in quantities to allow for shrinkage. After drying, the jewel is heated and allowed to cool. Excess niello is scraped off and the piece is polished, taking care not to remove the blackening.
Also known as millegrain, this style of embellishment uses very small beads of metal to add texture to fine jewelry. Platinum mille grain is popular with diamond jewelry to help offset the brilliance of the stones. Mille grain beads may edge a diamond’s bezel setting, frame a design, or enhance a row of graduated sized diamonds.
The grains are formed directly on the mount with the aid of a stainless steel tool which terminates into a tiny ridged wheel. Jewelers may have different mille grain tools to allow for larger or smaller spheres, round or grooved. The wheels are run along the surfaces of the mount to create rows of beading, though punches are used in locations where the wheel has trouble fitting. While mille grains are sometimes made in white gold, platinum’s malleability lends itself to creating especially fine beading.
Electroplate is a method that applies a thin coat of one metal to a base of a different metal. The piece of jewelry in question is dipped into a chemical bath. An electrical current runs through the solution, allowing tiny bits of the new material to adhere to the original piece. The new metal is usually from a single element, though alloys such as bronze are sometimes plated on.
Even precious metals at times receive a thin coat of a different metal to increase their beauty. Rhodium is electroplated onto white gold, platinum and silver pieces to help give the jewelry a mirror like finish. Gold is also electroplated, sometimes on fashion jewelry, or in other instances pure gold is plated onto eighteen or fourteen karat items.
Gold is most famous as a deep yellow beauty, though many know of white gold. Several other shades of gold exist, a result of blending the metal with other materials for strength. Copper, silver, palladium and other precious metals can combine with gold in specific ratios to create pink, green, grey and other hues. “Tricolor gold” refers to three shades used in the same piece.
Designer Paul Flato was fond of using tricolor gold in his 1940s creations. Modern mokume-gane also makes stylish use of this multicolor gold. Pieces made of tricolor gold may use its contrasting tones in an abstract pattern, or to create a pretty image such as a bouquet of flowers.
Bloom finishing is a way of brightening gold, with mysterious origins. The oldest known record of the technique dates to 1853, and enjoyed a heyday from 1870 to 1890. Rather than finishing gold through mechanical means, such as by hammer or lathe, bloom finish gets its look through the help of chemicals.
To create the finish, the gold piece is dipped into a boiling mixture of muriatic acid, potassium nitrate, water and salt. Between the heat and the ingredients, traces of copper, silver or other metal alloyed with the gold wash away, leaving a 24 karat surface. The process also leaves a flurry of tiny dents on the gold, creating a matte gleam. Light gleaming on the pure and textured metal is referred to as the “bloom.”
“Patina” refers to a coat that sometimes appears on metal, usually of a different color from the surface it covers. The phenomenon may arise as a result of age or exposure to air. In jewelry, some designers find this effect desirable, and may induce it on their creations.
Patina may be applied in many ways. One is through heating, another with the aid of chemicals, or a combination of the two. The methods used depend on the type of metal or alloy to be adorned, and the color and texture the designer wants to achieve. Copper alloys such as rose gold, shakudo and sterling silver are especially receptive to patinas, able to change color through a wealth of means. Vinegar, urea, sulfides, nitrates and chlorides may all be used to give fine jewelry an extra touch through color and texture.
Derived from the Japanese words for “red” and “copper,” shakudo is an alloy of gold and copper that resembles bronze it its plain state. The recipes to make shakudo are many with some calling for a blend of 4–10% gold to 96–90% copper, and others suggesting 75% copper with 4-25% gold and 5-20% antimony. No matter how it’s made, shakudo usually receives a dark patina to imitate lacquer work.
Molded shakudo may be used as an inlay, layered on top of copper, gold or silver. Traditionally it was used to make decorative elements on swords such has hand guards or grips. Today, shakudo is often used as an ingredient in mokume-gane.
Oxidized silver is a process in which the metal changes color, either naturally, or deliberately to suit a creative vision. The latter adds a dark patina to the silver through heating or via chemical applications. The new coating adds contrasting color and texture, gives a creation an antique look and protects the metal.
Jewelry grade silver is commonly alloyed with copper to give it strength while still being malleable enough to shape. The copper has a side benefit in aiding patina formation. To oxidize a silver-copper alloy, it may be heated until the copper reacts to oxygen in the air, or it may get a chemical coat, such as a sulfur compound. Depending on the chemical recipe, the final product may turn golden, black, green or brown.
The opposite of repoussé, chasing is a means of putting designs on metal through the act of indentation. The term partly derives from the French term “chasser,” “to drive out,” and partly from the English of the word, in the sense that the artists are pursuing their design. This technique is performed on the surface of the object, driving the metal from its smooth state.
Like its cousin, chasing is made with a combination of heat, hammers and chisels. Both methods date back millennia, with the burial mask of the Pharaoh Tutankhamen serving as an iconic example. Modern examples of chasing are found in sculpture and jewelry alike, as well as on accessories such as cigarette cases.
The brush finish provides a matte gleam to metal surfaces. It gets its name from how the base is brushed with stiff wires, creating a series of tiny indents onto the metal. The technique is used gold, platinum and less conventional jewelry metals such as titanium.
This finish is a popular choice for modern men’s rings. Men’s rings tend to less flamboyant than those designed for women, making subtle techniques stand out. The brush finish adds textural interest to a ring without being extravagant, and reflects light in a quiet manner.
Latin for “work scraped in between,” opus interrasile is a form of metal openwork used by Etruscan and Byzantine cultures, before the Romans expanded upon the technique. Opus interrasile was used from the 3rd century A.C.E. onwards, and providing a lasting impact on Byzantine jewelry. A form of openwork, this style features many tiny holes, like decorative mesh.
Opus interrasile is made with the aid of chisels or similar tools to pierce thin sheets of gold. Beforehand, a design would be traced onto the material. Once the pattern is complete, stones may be mounted on top. Opus interrasile may also serve as a background to other designs shaped onto the metal, such as a name or geometric images.