Jewelry Terms

Adularescence—The cloudy bluish white light in a moon- stone, caused by scattering of light.

Amorphous—Lacking a regular crystal structure.

Annealing—A gemstone heating process that can be used alone or to stabilize irradiated color.

Anniversary band—Ring with a row of gems of the same size and cut, typically in a channel setting.

Antique jewelry—Jewelry that is at least 100 years old.

Apparent clarity—A term used to describe the effects of treatments on the visual appeal of a gemstone.

Aqua regia—The only acid that can dissolve gold completely, so it’s used to test the fineness of gold alloys in the higher karatages.

Art Deco—A style prominent in the 1920s and 1930s that featured geometric patterns and abstract designs in contrasting primary colors.

Art Nouveau—A decorative arts movement (1890-1914) characterized by free-flowing lines and natural motifs.

Assembled jewelry—Jewelry made of two or more parts, sometimes created by different manufacturing methods, joined together.

Asterism—Crossing of chatoyant bands, creating a star in the dome of a cabochon.

Aventurescence—A glittery effect caused by light reflecting from small, flat inclusions within a gemstone.

Average girdle diameter—The result achieved by adding the smallest and largest girdle measure- ments of a round brilliant and dividing by two.

Baguette—A small, four-sided step cut that’s rectangular, square, or tapered.

Balance—A feature of design in which all elements harmonize in their appeal to the senses.

Bangle bracelet—A rigid, sometimes hinged, bracelet that slips over the wrist.

Base metals—Non-precious metals such as copper, zinc, tin, nickel, lead, and iron.

Bead setting—Setting style with gems held in place by rounded beads, usually pushed up from the surrounding metal.

Benefit—The value a feature holds for a customer.

Bezel—A thin metal strip that wraps around a gem to hold it in place.

Binocular microscope—A tabletop magnifier with two eyepieces.

Blemish—Characteristic or irregularity confined to the surface of a polished gemstone.

Bodycolor—A gemstone’s basic color, determined by its selective absorption of light.

Branded cut—Cutting style that’s developed, named, and promoted by a specific manufacturer.

Branded jewelry—Jewelry identified by its manufacturer, design house, or designer.

Brilliance—The brightness created by the combination of all the white light reflec- tions from the surface and the inside of a polished diamond.

Brilliant cut—Cutting style with triangular or kite-shaped facets that radiate from the center toward the girdle.

Britannia silver—95.8 percent fine, represented by a lion’s head or the seated figure of Britannia.

Brooch (pin)—Jewelry piece that attaches to a garment, often by a hinged pin and catch.

Bruting—Forming the basic face-up outline of a diamond to prepare it for faceting.

Cabochon—A smoothly rounded polished gem with a domed top and a flat or curved base.

Cabochon—A smoothly rounded polished gem with a domed top and a flat or curved base.

Calibrated sizes—Gemstone sizes cut to fit standard mountings.

Cameo—A gem carving style in which the design, often a woman’s profile, projects slightly from a flat or curved surface.

Carat—The international unit of measurement for gem weight. One carat equals 1/5 of a gram (0.200 g).

Channel setting—Setting style with gems held in grooved channels.

Characteristic color—The basic color of a fancy-colored diamond.

Chatoyancy—Bands of light in certain gems, caused by reflec- tion of light from many parallel, needle-like inclusions or hollow tubes.

Chemical composition—Kinds and relative quantities of atoms that make up a material.

Chemical formula—Written description of a material’s chemical make-up.

Clarity characteristic—Internal or external feature of a gemstone that helps determine its quality.

Clarity characteristics—The collective term for inclusions and blemishes.

Clarity—A gemstone’s relative freedom from inclusions and blemishes.

Cleavage—A smooth, flat break in a gemstone parallel to planes of atomic weakness.

Color center—A small defect in the atomic structure of a material that can absorb light and give rise to a color.

Color change—A distinct change in gem color under different types of lighting.

Color range—The selection of colors in which a gemstone occurs.

Color zoning—Areas of different color in a gem, caused by variations in growth conditions.

Colored stone—Any gem material other than diamond.

Commercial market—Market sector where average-quality gemstones are used in mass-market jewelry.

Conchoidal fracture—A curved and ridged fracture in a gemstone, extending from the surface inward.

Corrosion—Deterioration by a chemical action.

Craftsmanship—The care that goes into the fashioning of a polished diamond, as confirmed by its finish.

Crazing—The network of tiny fractures that develops when an opal loses moisture.

Crown angle—The angle formed by the bezel facets and the girdle plane.

Crown—Top part of the gem above the girdle.

Crystal structure—Regular, repeating internal arrangement of atoms in a material.

Culet—Small facet at the bottom of a finished gem.

Cupel—A small, porous vessel used in the assaying process.

Curb chain—Chain style with flattened oval links.

Custom jewelry—Jewelry made to order according to the customer’s specifications.

Cutting center—A city, region, or country with a large number of gemstone manufacturers.

Dealer—A wholesaler.

Density—The weight of an object in relation to its size.

Depth of color—The combination of tone and saturation that determines how noticeable a color is.

Depth—The distance from the table to the culet of a polished gem.

Design house—A jewelry retailer that caters to upscale clients, offering high-end jewelry, often designed by well-known jewelry artists.

Design—A diamond’s physical shape, including its proportions and durability, determined by decisions made during the fashioning process.

Designer cuts—Artistic gem cuts that aren’t limited to specific proportions or shapes.

Designer jewelry—Jewelry promoted as the creation of a particular designer.

Dispersion—The separation of white light into spectral colors.

Ductile—Capable of being fash- ioned into, and retaining, a new shape.

Durability—A gemstone’s ability to withstand wear, heat, and chemicals.

Durability—A metal’s ability to withstand wear, heat, and chemicals.

Edwardian (Garland) jewelry— Jewelry fashionable among upper classes in Europe and the US (1900-1915) that showcased high- quality gems and precious metals.

Electronic gold tester—A device that uses surface contact to measure the gold content in alloys.

Estate jewelry—Jewelry that was previously owned.

Eternity ring—Ring encircled with a row of closely matched gems, typically in a channel setting.

Extinction—Dark areas in a faceted transparent colored stone.

Eye-clean—Description for a gem with inclusions visible only under magnification.

Facet—A flat, polished surface on a finished gem.

Fancy cut—Any gemstone shape other than round.

Fancy shape—Any gemstone shape other than round.

Fancy-colored diamonds—Naturally colored yellow and brown diamonds that exhibit color beyond the Z range, or that exhibit any other color face-up.

Fantasy cut—A free-form cut that can feature alternating curved and flat surfaces.

Fashion jewelry—Inexpensive, or “costume,” jewelry, often com- posed of materials other than precious metals and gemstones.

Fashioning—Another term for gem cutting and polishing.

Feather—A collective term for diamond cleavages and fractures.

Feather—A general term for a break in a stone.

Feature—A characteristic or part of a piece of jewelry.

Federal Trade Commission (FTC)—A US Government agency that issues guidelines for the jewelry trade.

Figaro chain—Type of curb chain with one long link followed by several short ones in a repeating pattern.

Findings—Small components used to make or repair jewelry.

Fine color—The color or colors in a gemstone’s color range con- sidered by the trade to be the most desirable.

Fine—Free of impurities or alloying metals.

Fineness—A measure of purity for precious metal alloys.

Finish—The quality of the polish and precision of the cut of a fashioned gemstone.

Fire assay—An accurate but destructive test for determining the fineness of a gold alloy (also called cupellation).

Fire—The flashes of color you see in a polished diamond.

Fluid inclusion—Small pocket in a gem that’s filled with fluids and, sometimes, gas bubbles and tiny crystals.

Fluorescence—Emission of visible light by a material when it’s exposed to ultraviolet radiation.

Four Cs—Four value factors (clarity, color, cut, and carat weight) that describe the quality of a finished diamond.

Fracture filling—Treatment that involves injecting a molten glass sub- stance into a diamond’s surface-reaching feathers or laser drill-holes.

Fracture—Any break in a gem other than cleavage or parting.

Gem quality—Rough gem material that requires normal processing to produce a polished gem suitable for use in jewelry.

Gem species—A broad gem category based on chemical composition and crystal structure.

Gem variety—A subcategory of species, based on color, transparency, or phenomenon.

Gemology—The study of gems.

Girdle outline—Face-up shape of a polished gem.

Girdle—The narrow section of a finished gem that forms the boundary between the crown and the pavilion and functions as the gem’s setting edge.

Group—A family of gems from several closely related mineral species.

Guild store—Any jewelry store that specializes in high-end goods.

Half-shanking—Replacing a ring shank that has been damaged or become worn.

Hallmark—A British stamp that indicates the purity and origin of a precious metal.

Hardness—How well a gemstone resists scratches and abrasion.

Head—The part of a mounting into which the main gems are set.

Heft—The weight or heaviness of an object compared to its size.

High-end market—Market sector where fine-quality, expensive gemstones are used in unique, handcrafted jewelry pieces.

Hue—The first impression of an object’s basic color.

Hue—Your first impression of a color; the basic color of an object.

Included crystal—A mineral crys- tal trapped within a gem as it grows.

Inclusion—Clarity characteristic totally enclosed in a polished gemstone or extending into it from the surface.

Industrial quality—Rough gem material suit- able for use in tools, drills, abrasives, and other industrial applications.

Inorganic—Composed of, or arising from, non-living matter.

Intaglio—A design engraved into the surface of a gemstone.

Iridescence—A rainbow effect created when light is broken up into spectral hues by thin layers.

Irradiation—A treatment that changes the color of a gem by exposing it to radioactive materials.

Karat—A unit of measure for the fineness of gold, abbreviated “K” or “Kt.”

Karat—A unit of measure for the fineness of gold, equal to 1/24 part, abbreviated “K” or “Kt.”

Labradorescence—A broad flash of color in labradorite feldspar that disappears when the gem is moved.

Laser drilling—Treatment that involves using a concentrated beam of laser light to reach a diamond’s dark inclusions and to disguise or eliminate them.

Length-to-width ratio—Comparison of the length to the width of marquise, emerald, pear-shape, oval, and princess cuts.

Light carat—A trade term for a diamond that weighs between 0.96 ct. and 0.99 ct.

Light half—A trade term for a diamond that weighs between 0.45 ct. and 0.49 ct.

Lion passant—A lion walking with its farthest forepaw raised; Britain’s mark for sterling silver.

Alloy—Mixture of two or more metals.

Loupe clean—Term that describes a diamond that might have surface blemishes, but shows no inclusions under 10X magnification.

Loupe—A small, portable magnifying lens used for examining gemstones.

Luster—The appearance of a material’s surface in reflected light.

Make—The qualities of a faceted diamond’s proportions and finish.

Malleable—Ability to be stretched in all directions without breaking.

Manufacturer—An individual or company that cuts and polishes diamonds and colored stones.

Masterstones—A set of color comparison diamonds that defines GIA’s diamond color grades in the normal (D-to-Z) range.

Melee—Very small faceted diamonds.

Metric carat—The international unit of measurement for gem weight. One carat equals one-fifth of a gram (0.200 g).

Milk and honey—A two-toned effect seen when a chatoyant gem is positioned at right angles to a light source.

Mineral—A natural, inorganic substance with a characteristic chemical composition and usually characteristic structure.

Mixed cut—A cutting style that combines brilliant-cut and step- cut facets.

Mohs scale—Ranking of the relative hardness of 10 minerals.

Mokume-gane—A technique of laminating different colored metals and bending them in pat- terns that resemble wood grain.

Mounting—Jewelry item with space for holding gems.

Natural gems—Gems produced by natural processes, without human help.

Near-colorless—A general term for diamonds in the G-to-J color range.

Near-gem quality—Rough gem material that requires substantially more processing than gem-quality rough to produce a polished gem suitable for use in jewelry.

Noble metal—Any metal that resists corrosion and tarnishing.

Normal color range—Range of diamond colors from colorless to light yellow and light brown.

Objection—An obstacle that might delay—or even stop—the sale.

Organic—Once living, or produced by a living organism (plant or animal).

Orient—Iridescence seen in some natural and cultured pearls and mother-of-pearl.

Padparadscha—A rare pinkish orange sapphire.

Parting—A flat break in a gemstone parallel to a twinning plane.

Parting—The separation of gold from silver in a refining process.

Pavé setting—Bead setting with many small gems placed close together, often in a honeycomb pattern.

Pavilion angle—The angle formed by the pavilion main facets and the girdle plane.

Pavilion bulge—Larger-than-usual pavilion angles on the middle tier of facets, designed to add weight to a step-cut stone.

Pavilion depth percentage—The distance from the bottom of the girdle plane to the culet, expressed as a percentage of the average girdle diameter.

Pavilion—Lower part of a faceted gem below the girdle.

Per-carat price—The price of the gem divided by its carat weight.

Period jewelry—Jewelry from a recognized time period.

Phenomenon—An unusual opti- cal effect displayed by a gem.

Piqué—A general term for included stones.

Plating—Depositing a metal elec- trically or applying it mechanically to protect, enhance, or change the color of another metal.

Play-of-color—The flashing rainbow colors in opal.

Pleochroism—When a gem shows different bodycolors from different directions.

Plot—A color-keyed diagram of a gemstone’s significant clarity characteristics.

Plumb gold—Karat gold whose actual gold content falls within specified narrow tolerances of its stated gold content.

Point—One one-hundredth of a carat (0.01 ct.).

Polish—The overall condition of the facet surfaces of a finished diamond.

Porosity—A metal defect that appears as pits or holes in the surface.

Precious metals—Metals valued in jewelry, specifically gold, platinum, and silver.

Prong (claw) setting—Setting style consisting of narrow metal supports that hold a gem in its mounting.

Proportions—The angles and relative measurements of a polished gem, and the relationships between them.

Provenance—A historical record of ownership or origin for a gem or piece of jewelry.

Quality mark—A stamp that indicates the purity of a precious metal.

Refraction—The change in speed and possible change in direction of light as it travels from one transparent material to another.

Refractive index (RI)—A measure of the change in the speed and angle of light as it passes from one material to another.

Remounting—Removing a gem (or gems) and resetting them in a new mounting.

Repronging—Replacing a prong.

Retipping—Rebuilding the top of a prong.

Retro jewelry—Jewelry of the 1940s, characterized by sculp- tured curves in yellow or rose gold and floral, bow, and mechanical motifs.

Ring stretcher—A device that stretches a ring shank to make it larger.

Saturation—A color’s strength or intensity, ranging from a dull hue to a pure, vivid hue.

Schwerter’s solution—A liquid chemical mixture used for testing silver purity.

Scintillation—Flashes of light displayed by a polished gemstone when the gem, the observer, or the light source moves.

Selective absorption—Process by which a material absorbs some components of visible light and returns others.

Setting style—The way a gem is secured in its mounting.

Setting—The act of placing gems in jewelry.

Shank—The part of a ring that encircles the finger.

Shape—The face-up outline of a gem.

Shoulder—One of the two sides adjacent to the rounded end of a pear or oval shape. Symmetry—The precision and balance of a finished gem’s cut.

Silk—Group of fine needle-like inclusions.

Simulant—A natural or manmade material that resembles a gem (also called imitation).

Single cut—A round stone with 17 or 18 facets.

Solitaire—Jewelry piece with one main gem, typically a diamond.

Source—A gem-producing area, or a particular mine in that area.

Specific gravity (SG)—Ratio of the weight of a material to the weight of an equal volume of water.

Stability—How well a gemstone resists the effects of light, heat, and chemicals.

Standard round brilliant—A round brilliant-cut stone with 57 or 58 facets. Often called a full cut.

Station—A set position for a design element in a necklace, usually set apart from other stations at regular intervals.

Steam cleaner—A machine that cleans jewelry with high-pressure steam.

Step cut—A cutting style that features long, narrow facets in rows (usually three) parallel to the girdle on both the crown and pavilion.

Step cut—Cutting style with mainly square and rectangular facets arranged in concentric rows.

Stud earring—An earring with a small buttonlike ornament, mounted gem, or cultured pearl on a metal post designed to pass through a pierced earlobe.

Style—The arrangement of a stone’s facets.

Synthetic gem—A laboratory creation with essentially the same chemical composition, crystal structure, and properties as its natural counterpart.

Table percentage (size)—Table size expressed as a percentage of a round brilliant’s average girdle diameter.

Take-in—A procedure for receiving customer jewelry for repair, appraisal, or cleaning.

Tarnish—Surface discoloration caused by contact with sulfur-rich substances, including air. Tarnish is a mild form of corrosion.

Tennis bracelet—A flexible bracelet set with a line of small matched round gems, typically diamonds.

Thermal shock—Damage caused by sudden, extreme temperature changes.

Tone—A color’s degree of darkness or lightness.

Total depth percentage—Table-to-culet depth, expressed as a percentage of average girdle diameter. Wing—One of the two sides near the point of a marquise, pear, or heart shape. Total gem weight—The combined weight of all the stones in a piece of jewelry that contains a variety of gems.

Total weight—The combined weight of all the diamonds in a piece of jewelry that only contains diamonds.

Touchstone test—A process that compares how gold alloys of known and unknown fineness react to acid.

Toughness—How well a gemstone resists breaking and chipping.

Trace elements—Atoms in a gem that aren’t part of its essential chemical composition.

Trade terms—Terms often used in the jewelry industry to describe particular gemstone colors or link gems with specific geographic locations.

Trademark—A word, phrase, logo, symbol, or design that’s registered to identify the manufacturer of an item.

Transparency—Degree to which a material allows light to pass through it.

Trunk show—Special retail event where customers can meet with a jewelry designer or manufacturer’s representative.

Twinning plane—Location of a change of direction in a gem- stone’s crystal structure during growth.

Ultrasonic cleaner—A machine that cleans jewelry with high-frequency sound waves in a liquid solution.

Ultraviolet (UV)—Light wavelength that’s invisible to the human eye

Underkarating—Misrepresenting the precious metal content of a jewelry item.

Value factors—Features used to judge the quality and value of all gemstones.

Victorian jewelry—A variety of styles popular during the reign of England’s Queen Victoria (1837- 1901).

Window—An area of weak saturation in a transparent gem- stone’s bodycolor that usually results from the way the gem was cut.

Source: GIA

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