Collectors Glossary

Below are lists of common terms collectors are likely to encounter in various categories.

Originally used for industrial purposes thanks to its ability to withstand heat, Bakelite was invented in 1907 by Leo Baekeland, and was one of several patented plastic resins (along with Plaskon, Beetle, and Catalin) that were popular in the 1920s and 30s. Associated with Art Deco style objects.

A piece of ceramic that has been fired but not glazed.

A design in relief that’s created when material is carved from the surface of shell or stone. Often used to refer to any relief depiction of a human head presented in profile.

A technique in which filaments of metal (often gold or copper) are soldered to a surface to create compartments that are then filled with ground enamel, fired, and polished.

An engraving technique that uses mechanical means to create precise, intricate, and repetitive patterns and designs, usually in metal.

The opposite of a cameo, an intaglio is achieved when a material such as stone is carved to produce a void in its surface. Often used in seals and signet rings.

A process developed in the 1850s in which pottery is covered with opaque enamel made from metal oxides, fired, painted, fired again, and then covered one more time in clear enamel.

An ancient glass technique, popularized in the 19th century, in which rods of fused glass are cut into cross sections to reveal patterns, frequently resembling flowers.

A type of molding whose profile resembles an S-shape curve.

A variation of cloisonné in which enamel is framed by walls of fine wire or metal but not backed, allowing light to pass through the translucent enamel.

In an effort to make everything from radios to railroad trains look modern, designers streamlined their creations, producing a look that became ubiquitous during the heyday of Art Deco and during World War II.

A plasticized form of nitrocellulose and camphor developed in 1868 to make billiard balls, which sparked when they collided due to the material’s flammability. Repurposed in the first half of the 20th century for use in costume jewelry.

Decorating a piece of metal on its surface, usually with hand tools that leave marks and make indentations but do not remove any of the surface material.

Decorating a piece of metal on its surface, as described in chasing, but from the back of the piece. The resulting indentations are thus raised on the front. Also called repoussé.

When wire (usually gold or silver) is twisted into delicate patterns before being soldered into a larger frame.

Gold filled
A misnomer since the gold is actually visible on the surface. In the United States, the gold a customer sees must equal at least 1/20th the weight of the base metal below it in order for a product to be sold as gold filled.

Gold washed
An even thinner layer of gold over base metal than rolled gold.

Goldtone or gold-tone
A term used by costume-jewelry manufacturers and designers to describe their gold-plated or gold-washed pieces.

Fossilized coal found near Whitby, England. Used primarily in mourning jewelry.

Developed in the 1930s, this clear acrylic was less expensive to produce than Bakelite, Galalith, and Catalin and more chemically stable than celluloid.

A type of leaded glass that was invented by French jewel designer Georges Frédéric Strass in 1724. When cut and polished with metal powder, this precursor of the rhinestone appears to shimmer like a diamond. Also called “diamante” or “strass.”

An alloy invented in 1720 by Christopher Pinchbeck, who discovered that a certain combination of copper and zinc resembled gold.

Rolled gold
Similar to gold filled, but with no weight requirement.

Gold-plated sterling silver.

A type of hardened rubber.

A watch that measures time intervals like a stopwatch.

A watch that has been certified by the Official Swiss Chronometer Testing Institute not to lose more than four seconds per day, nor to gain more than six.

A “complicated” watch is one that displays more than just hours, minutes, and seconds. Complications include annual calendars and time zones. So-called “grand” complications include moon phases, chronographs, and sky charts.

A device that converts the pressure of a spring or coil into a fixed release of movement.

The ability to push a single button on a watch to stop, reset, or restart its chronograph function.

A cone-shaped piece in a mechanical clock or watch that is attached to a spring via a length of chain.

A unit of measure (2.256mm) designating the size of a watch movement.

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