If you are a novice at buying vintage jewelry, especially on EBAY, you will probably find many of the descriptions a bit confusing due to the terminology used to describe the pieces.  Sometimes, you might start getiing frustrated.  You willl find that collecting vintage jewelry is fascinating when you understand what the piece is and its features. 

Many of the great books on collecting Vintage Jewelry do not have good definition sections.  I found that the book Signed Beauties of Costume Jewelry Volume II Identification & Value by Marcia Sparkles Brown has a definition section that is really helpful.  Many of the definitions below are from this book.

TERMINOLOGY:

Amethyst  - natural gemstone in shades from lavender to purple.  Costume jewelry frequently uses imitation rhinestones in the same shades.

Antique - costume jewelry made before 1950.

Art Deco - Jewelry made from 1910-1930 with geometric lines and bold colors.

Art Nouveau - Jewelry made from 1890-1915 where the designs centered on a poetic interpretation of nature.

Articulate - divided into distinct segments that give the piece mobility

Aurora Borealis - microscopic layers of different materials vacuum plated to glass for an iridescent coating.  Introduced in 1953.

Baguette - elongated, faceted, straight sided stones.

Base metal - often called pot or white metal.  It is composed of 92% tin with added cadmium, lead and zinc.  Used to form the first stage of costume jewelry.

Bib - a necklace with three or more strands interwoven in a pattern to flow as one.

Black Diamond - smoky colored rhinestones.  Name given by the Weiss company.

Brass - alloy of copper, tin and zinc.  Dull yellow metal.  Earlier antique costume jewelry pieces sometimes used brass as the base metal.

Bridge - suspended decorative arch attached to each end.

Brooch - from the  French word "broche" which means to skewer.

Cabochons -non-faceted, rounded, dome stones.  Usually flat on the bottom.

Carnival Glass - American made iridescent glassware, imitated in rhinestones.

Cartouche - plate bearing company name applied to the back of vintage jewelry.

Chatelaine - formerly, long chains fastened at the waist that were hung with the necessary daily items of a housekeeper.  Now it is the name for two brooches connected by one or more chains.

Chaton - most common faceted rhinestone.  A cut with 9 to 12 facets, flat tabletop surface, and a bottom that comes to a point.

Citrine - q;uartz stone ranging from yellow to gold in color.  Imitated in rhinestones.

Clipmates - two fur clips on a slide that when completed can be worn as a brooch.  Trifari trademark.

Collectibles - costume jewelry manufactured after 1950.

Costume Jewelry - jewelry not containing precious jewels or metals.

Crackle Glass - lumpy, molded glass.

Diamente - imitation diamonds.  Another name for clear rhinestones.

Demi-parure - two matching pieces of the same design.  Often called a set.

Dentelles - unfoiled crystal glass, formed in a mold and hand cut.  Popular from 1930s to 1950s.

Dichroic - having the property of presenting different colors in two different directions, by transmitted light.

Dress clip - hinged clasp brooch worn singularly as part of a pair.  Inserted on the neckline, bunching the material together to create a lower neckline with ornamentation.

Duette - two clips mounted on a brooch frame.  Made by Coro.

Facets - cuts made to shape stones and enhance lights.

Faux - French for "false".  Used to denote manmade copies of gem stones.

Filigree - metal wire scroll work that is open, airy, lacy

Flat-back - used to describe a stone that is flat on the back

Foil backing - backing applied to rhinestones in a vacuum plating process using very thin gold or silver metal.  This allows light to bounce off the stone and sparkle.

Fur clip - two long prongs on a spring steel, allowing the decorative clip to be worn on a heavy fabric or furn.

Hallmark - mark on back of jewelry denoting gold or silver content.

Hang Tag - removable paper or metal tag bearing company name attached after production is completed.

Japanned - finished or plated using a black, coal-tar derivative.

Logo - company trademark

Lucite - transparent acrylic plastic.  DuPont trade name for plexiglass.

Marquise - stone, oval shaped with points on each end, resembling an eye.  Also called navette.

Navette - stone, oval shaped with poings on each end, resembling an eye.  Also called Marquise.

Nodder - individual pieces mounted on small springs to vibrate when moved.  Also called a trembler.

Opalene - manmade imitation of opal.

Open Work - actual design cut into metal, allopwing daylight to filter iu,

Parure - more than two matching pieces of jewelry.

Pave - stones placed close together, with a minimum of metal showing.  Literally paving over the metal.

Pillbox - small container carried in purse to hold medications.

Plating - jewelry dipped in copper, then dipped into electro - magnetic acid bath, which forms a thin layer of finishing.

Pot metal - often called base  or white metal.  It is composed of 92% tin with added cadmium, lead and zinc.  Used to form the first stage of costume jewelry.

Rhinestone - leaded glass stones with foil backing.

Rhodium - non-tarneshing silver colored finish.  Member of the platinum family of metals.

Set - more than one matching piece of the same design.  Also called a demi parure.

Suite - more than two pieces of the same design, also called a parure.

Sweater guards - two alligator pinch clips chained together to hold a sweater front together.

Topaz - gemstone usually ranging in color from yellow to orange.

Trademark - name of company placed on back of jewelry.

Vacuum plated - name of process used to foil the backs of rhinestones.

Vermeil - a gold wash over sterling silver.  Can be pink or yellow gold finish.

White metal - often called pot or base.  It is composed of 92% tin with added cadmium, lead and zinc.  Used to form the first stage of costume jewelry.

Now that you have most of the terminology down, go and buy some great vintage jewelry.  You will probably get hooked.