Jade
A semi-precious stone that ranges in color from green to white to lilac to brown to almost black. Translucent jade is more highly valued than opaque jade. Jade is often cabochon set; stones with imperfections are often carved (the imperfections are simply carved away). Two different minerals are known as jade: jadeite and nephrite. Jadeite is the harder of the two; it is usually used in jewelry production. Nephrite is slightly softer and is often veined; it is used in carvings, for making beautiful bowls and vases. The Chinese have prized jade for thousands of years and regarded it as having medicinal properties when worn or ingested as a powder. Natural jadeite is called Type A or Grade A jade (waxing or wax dipping is allowed). Jadeite that had been bleached and then treated with polymers (plastic) or waxes is called Type B or Grade B jade (it is less durable than natural jade). Jadeite that had been dyed is called Type C or Grade C jade (the color is less durable than that of natural jade). Jadeite that has been both dyed and impregnated with polymers is called Type B+C or Grade B+C.

Jade Glass
Jade glass is translucent green glass that is designed to imitate jade.

Jadeite
Jadeite is the harder of the two varieties of jade. Jadeite is harder (compared to nephrite) and is usually used in jewelry production.

Japanned
A Japanned finish in jewelry is when metal is finished with a lustrous, black lacquer. The Maltese cross brooch above is by Weiss; it has red paste stones and a Japanned finish.

Jasper
A common, opaque, semi-precious stone that is found in many colors, including white, brown, yellow, red, and green. Jasper is found all over the world; it is often striped, speckled, and multi-colored. Jasper has been used for intaglio carvings. Jasper is a type of quartz belonging to the chalcedony family. It is often sealed with petroleum products. Jasper is sometimes dyed to resemble lapis lazuli and misleadingly called "Swiss lapis." Jasper has a hardness of 6.5 to 7.0.

Jasperine
Jasperine refers to any type of banded jasper.

Jasperized Wood
Jasperized wood (also called xyloid jasper) is petrified wood. It is wood that has fossilized - all the original chemicals have been replaced with minerals, making a stone-like replica of the original wood.

Jasper Ware
Jasper ware (also spelled jasperware) is a type of porcelain (high-fired white kaolin clay) made by the Wedgwood company. It is made into molded cameos that are made into pins, pendants, and necklaces.

Jeanne
Jeanne was a mark used by Mark Dottenheim of NY, NY, for costume jewelry, often figural. This mark was first used in October 1919. The gold-plated Jeanne pin above depicts a bird's nest with tiny pearl eggs.

Jelly Belly
A jelly belly is a piece of jewelry (usually a pin) that has a clear lucite or glass center. The Trifari jelly belly fish pin above has a faceted glass belly.

Jensen, Beorg
Georg Jensen (1866-1935) was a Danish silversmith, ceramic artist, and sculptor. Jensen's modern-style silver jewelry is often adorned with semi-precious stones and is avidly collected. Jensen's workshop grew to have branches in Australia, New York, USA, and Toronto, Canada.

Jet
Jet (also known as gagate) is fossilized coal. It is a hard, lightweight lustrous black stone that was used in mourning jewelry during the Victorian era (especially after Queen Victoria's husband died in 1861 and she went into long period of mourning, greatly affecting jewelry fashion). Jet is frequently cabochon cut. Most jet is from Whitby, England; jet has been mined near Whitby (on the Yorkshire coast of England) since prehistoric times. It is also found in Spain, France, Germany, and Russia, but these other sources are said to be inferior to the harder, more elastic Whitby jet. Jet has a hardness of 2.5-4 (quite soft) and a specific gravity of 1.30-1.35 (it is relatively lightweight). Jet leaves a brown streak. When burnt with a red-hot needle, jet smells like coal. Black glass and plastics are often used to imitate jet (glass is much heavier and harder than jet) - jet is warm to the touch.

Jewelry
Jewelry (spelled jewellery in Britain) is articles of personal adornment, like rings, necklaces, bracelets, cuff links, and pins. Jewelry is made from metals (especially gold and silver), stones, glass, plastic, and other materials.

J.J.
J.J. is a registered trademark of the Jonette Jewelry Compant, East Providence, R.I. This costume jewelry company was orignially called the Providence Jewelry Co.; it was founded in 1935 by Abraham Lisker. When Abraham Lisker's brother Nathan joined the company, the name was changed to Lisker & Lisker Inc. Production was halted during World War 2. After the war, the company was called the Jonette Jewelry Company. Marked with the initials "J.J." their jewelry is mostly figural and novelty pins, including Christmas pins. The poodle above is a J.J. figural pin.

Jobber
A jobber is a wholesale company that manufactures jewelry pieces by the job for other companies. For example, De Lizza & Elster was a jobber that supplied pieces for Weiss, Kramer, Kenneth J. Lane, Hobe, Celebrity, Hattie Carnegie, Alice Caviness, Karu, and many others.

Job's Tears
Job's tears (Coix lacryma-jobi) is a wild tropical grass plant that has very hard seeds. The white seeds are used as beads in jewelry. The seeds are dried, dyed or painted, polished, drilled and then strung into necklaces and bracelets.

Jomaz
Jomaz (or Mazer) is a costume jewelry mark used by the Joseph J. Mazer company (founded in NY, NY, in 1927). Early pieces are marked "Mazer Bros;" later pieces are marked JOMAZ or MAZER. They went out of business in the 1970's. They make high-quality jewelry like the gold-plated earring above with pearl and paste accents.

Juliana
Juliana jewelry is distinguished by many beautiful, brightly-colored glass stones of different shapes and sizes (often including speckled or "painted" stones), with very little metal showing in the pieces. The well-made designs are very feminine, and often use cluster settings. Stones were either prong-set (usually with four prongs) or glued in. Juliana bracelets usually have five links and a fold-over clasp (plus most have a safety chain with a spring ring). Juliana pieces were marked with only a paper hang tag (a detachable tag), so positive identification is not usually possible. Juliana jewelry was produced from 1950 until the 1960s, and pieces are now highly prized by collectors. Juliana pieces were manufactures by the De Lizza & Elster company. A few other companies, including "Gloria" (perhaps made by G. Fox and Co. of Hartford, CT) and "Tara," sold pieces similar to Juliana pieces.

Juliana-Style
Juliana-style jewelry is unsigned costume jewelry that resembles Juliana jewelry (see the previous entry)s, but the piece's origin in undetermined.

Jump Ring
A jump ring is a circular metal ring with an opening. It is used to attach two other rings or links, and is then soldered or pressed shut.