About Jewellery » Glossary of Terms

Alloy: Mixture of two or more metals.

Blemish: Clarity characteristic that is confined to the surface of a polished gemstone.

Brilliance: The brightness created by the combination of all the white light reflections from the surface and the inside of a polished diamond. A more properly proportioned cut results in a more brilliant diamond.

Brilliant Cut: Cutting style of a round diamond with triangular or kite shaped facets that radiate from the centre toward the girdle. A brilliant cut contains 57 or 58 facets, depending on whether there's a culet.

Carat: Measurement used for the weight of a diamond. One carat is equal to 100 points or one fifth of a gram (0.200 g).

Clarity: A graded scale that measures the amount of inclusions within a diamond. The scale set by the Gemological Institute of America ranges from flawless (FL) to severely included (I3).

Clarity Characteristic: The collective term for inclusions and blemishes.

Cloud: Minor inclusions clustered within a diamond.

Color: Color tones of a diamond that are graded on a scale of D (colorless) to Z (yellow/brown).

Crown: Top part of the gem above the girdle.

Culet: Small facet at the bottom of a finished gem (at the point).

Cultured pearls: Pearls cultivated by artificial insertion of a small bead, often made of mother-of-pearl and mantle tissue, into an oyster. Patented by Kokichi Mikimoto in 1916.

Cut (Make): The proportion and symmetry of a diamond determines the stone's brilliance and dispersion capabilities.

• Ideal Cut: A round diamond that is perfectly proportioned.
• Very Good Cut (Premium): A proportioned cut that maximizes brilliance, reflection and dispersion. Meets the highest standards and dimensions for a quality diamond.
• Good Cut: An acceptable and more reasonably priced cut with decent proportions.
• Fair Cut: While still capturing some sparkle, this cut is lacking in brilliance when compared to the Good and Very Good cuts.
• Poor Cut: A clearly dull and lifeless diamond that sacrifices proportion and quality.

Depth: A diamond's height from culet to table.

Depth %: Height divided by width. Determines brilliance and sparkle.

Durability: The ability (in gems or metals) to withstand wear, heat, and chemicals.

Eye-clean: When viewing with the naked eye, a diamond with no visible inclusions or imperfections.

Facet: A gemstone's flat, polished surface.

Fancy Cut: Any gemstone shape other than round.

Fancy Coloured Diamonds: Naturally coloured yellow and brown diamonds that exhibit colour beyond the Z range, or that exhibit any other colour face up.

Feather: A collective term for diamond cleavages and fractures.

Fineness: A measure of purity for precious metal alloys.

Fire (Dispersion): Reflected spectral colors that radiate - flash - from the inside of a polished diamond.

Fluorescence: When exposed to ultraviolet light, an illuminating color that glows from the diamond surface, which usually doesn't affect appearance or quality.

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

Freshwater pearl: A pearl produced by a fresh water mollusk.

Girdle: A diamond's outer edge or periphery. It is a very narrow section of the gem that forms the boundary between the crown and the pavilion and functions as the gem's setting edge.

Hardness: How well a gemstone resists scratches and abrasion. See also Moh's Scale.

Head: An attachment that holds a gemstone. Usually 4 prongs, but can be from 3 to 12 or more as a rule.

Inclusion: Clarity characteristic totally enclosed in a polished gemstone or extending into it from the surface. May or may not be visible to the naked eye, but noticeable when magnified.

Irritant: Small parasite or particle which catalyzes the pearl-growing process. Can be naturally occurring or artificially inserted.

Karat: A unit of measure for the fineness of gold, equal to 1/24 part, abbreviated 'K' or 'kt'.

Luster: A combination of the pearl's exterior shine and glow from within. Created by light reflected from tiny crystals in the nacre.

Mabe pearl: Cultured pearls grown against an oyster's shell rather than in an oyster's tissue. The result is a semi-spherical pearl with a relatively flat back.

Mantle: Soft tissue located inside an oyster. Man-made pearls are formed when the mantle surrounds a surgically inserted nucleus.

Mohs hardness scale: A scale developed by Friedrich Mohs to determine the relative hardness of minerals and other objects. The scale assigns numbers 1-10 to specific minerals, softest to hardest, using a scratch test.

Mother of Pearl: The iridescent lining of an oyster's shell. Often used as a nucleus for a man-made pearl.

Natural pearls: Pearls formed by an irritant without surgical implementation.

Nacre: (Nay-ker) The crystalline substance secreted by an oyster to form a pearl. The microscopic crystals of nacre refract light to produce a pearl's color and luster.

Nucleus: The object which is artificially inserted into a pearl's mollusk during the cultivation process. This becomes the center of a finished pearl.

Orient: The rainbow effect that is on or just below the pearl's surface.

Pavilion: The lower part of a faceted gem below the girdle.

Point: One hundredth of a carat.

Polish: The external finish of a stone, which ranges from excellent to poor.

Princess Cut:

Ring Size: See Numbers for more information on ring and finger size, including a table of conversions between European, Japanese and North American scales.

Scintillation: The flashes of light you see when the diamond, the light or the observer moves.

Shank: The part of the ring that encircles the bottom of the finger.

Side Stone: A stone set alongside or encircling a center stone.

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

Sparkle: The amount of reflected light that radiates from a diamond's surface and combines both fire and brilliance.

Surface markings: Imperfections on the pearl's surface. Often described as spots, blisters, or indentations.

Symmetry: The overall unity and proportion of a stone's cut. Symmetry ranges from poor to excellent.

Synthetic Gem: A manmade gem with essentially the same chemical composition, crystal structure, and properties as a natural gem.

Table: The largest facet on the top of a gemstone.

Table %: The total diameter of a gemstone's table in direct proportion to its overall width. A table which is too small or too large will negatively affect its brilliance and dispersion

Tone: A classification scale, ranging from light to dark, which indicates (specifies) the color intensity of gemstones and fancy colored pearls.

Toughness: How well a gemstone resists breaking and chipping.

Uniformity: The grading system used to denote how well pearls in a piece of jewelry match one another. Uniformity can be excellent to poor.

Thanks primarily to the Gemological Institute of America for this glossary of terms.