Terminology

A

Adamas

Greek word for indestructible; origin of the word diamond

Antwerp

Center for the distribution of rough and polished diamonds; more than half of the world's production of rough, polished, and industrial diamond passes through this city

Appraisal

Official valuation document made by a certified gemologist and expert in field of diamonds and metals

Asscher

Diamond shape named after the world-renowned cutter Joseph Asscher; square with cut corners

B

Baguette

Rectangular-shaped step cut most commonly used to complement larger diamonds

Bezel

Setting in which metal rim secures diamond at the girdle; permits diamond's light-throwing abilities while protecting the stone

Black Diamond

Diamond saturated with graphite inclusions

Bourse

Diamond-trading markets where members buy and sell goods

Bow-tie Effect

Diamond-trading markets where members buy and sell goods

Brilliant-cut

Triangular-shaped facets, typically numbering 57, pointed toward the outer part of the diamond

C

Canary

Fancy color diamonds with an intense or vivid yellow color

Carat (ct.)

Unit of metric measurement used for diamonds; one carat equals .2 grams, or .007 ounces

Certification

A document issued by an independent gemological laboratory that details the vital characteristics of a diamond along with carat, color, clarity, and cut

Channel

Setting with uniform diamonds mounted in a grooved channel; diamonds are secured as a group and are not separated by metal as in other setting styles

Clarity

Internal and external characteristics of a diamond visible under 10x magnification

Clasp

Closure used in bracelets and necklaces for security

Color

Rating of the degree of color of a diamond as compared to a master stone(s)

Crown

Portion of faceted diamond above the girdle

Crown Angle

Relationship of the crown to the girdle; measured in degrees

Culet

Small facet polished at the bottom of the pavilion

Cushion

Square shape with rounded corners

Cut

Refers to diamond shape and/or quality of cut

Cut Grade

GIA rating of polish, symmetry, weight ratio, brightness, scintillation, and fire

D

Depth

Measurement of diamond from the top of the crown to the bottom of the pavilion

Depth Percentage

Width ÷ depth = depth°

Diamond

Mineral composed entirely of the element carbon

Dispersion

Light that shoots through the top of the diamond displaying a color spectrum

E

Emerald

Diamond cut shaped after the way emerald gemstones are cut; shorter in length than a proper rectangle

F

Facet

Flat, polished surface on a diamond

Fancy Color

Color in a diamond that increases the stone's value

Fancy Shapes

Any shape other than round-cut

Finish

Quality of a diamond's polish and symmetry

Fire

Light that enters a diamond and is then returned to the viewer

Fluorescence

Light emitted from a diamond when the stone is exposed to UV light; often a blue hue

G

Girdle

Band across widest part of a diamond; divides the crown and pavilion

Gold

Chemical element Au; most common metal for jewelry because of its beauty and durability

Gold Purity

Expressed in karats ('K'). Gold is alloyed with other metals such as silver, copper, zinc, or silicon to produce purities less than 24 carat. Finest gold used in jewelry is 18K (75% pure) or 14K (58.5% pure)

Grain

1/4 of a carat; 1ct = 4 grains

Grams

Unit of weight measurement; used for gold weight

H

Heart

A pear-cut with two rounded edges instead of one

Hearts and Arrows

Ideal-cut symmetrical diamonds will exude arrows when viewed "face up" and hearts when viewed "face down;" can be seen with certainty only under a special microscope

I

Ideal-cut

Polished diamond with exceptional make and light performance

Inclusion

Internal characteristic in a diamond

Intensity

Concentration of color in fancy color diamond; value is closely tied to a colored diamond's intensity grade

J

Johannesburg

Diamond center in South Africa

K

Kimberlite

Volcanic rock formation in which diamonds are found

L

Laboratory

Facility equipped with scientific tools to verify natural diamonds and grade their characteristics

Laser Inscription

Caption on diamond girdle used mostly for identification

Loupe

Magnifying glass used in the diamond industry

M

Make

Refers to the craftsmanship of a diamond's cut and finish

Marcel Tolkowsky

Published modern diamond cutting method in 1919; known as the originator of the modern brilliant round-cut diamond

Marquise

Twice as long as it is wide with pointed ends; named after Marquise de Pompadour's smile

Master Stone

Diamond of a predetermined color that is used for comparison in diamond markets and laboratories around the world

Measurements

Width1 x width2 x depth (expressed in millimeters)

Mix-cut

Diamond cutting method using brilliant-cut and step-cut faceting techniques

N

O

Oval

Elongated round-cut diamond

P

Pave

Multiple small diamonds set as closely together as possible in two or more rows

Pavilion

Portion of faceted diamond below the girdle

Pavilion Angle

Relationship of the pavilion to the girdle; measured in degrees

Pear

Diamond-cut comprised of the brilliant round-cut and marquise-cuts; resembling tear drop

Platinum

Chemical element Pt; silver-white in color and used in its pure form for jewelry

Polish

Quality and smoothness of polished diamond surface

Pressure

Setting type that uses pressure to hold multiple diamonds in a mounting

Princess

Square cut diamond with 90-degree-angled corners

Prong

Setting type in which diamonds are held in place by fine metal prongs

Q

R

Report

Gemological certificate

Rhodium

Process in which gold is dipped in a protective alloy to prevent tarnishing and make the metal white

Rough

Any uncut diamond

Round

Round-shaped brilliant-cut diamond

S

Scintillation

Reflections from the facets of a diamond seen as the stone is turned in the light

Solitaire

A ring containing a single diamond

Star Facets

Triangular facets along the table

Step-cut

Rows of elongated facets that act like mirrors

Symmetry

Shape and precision of facet arrangement in a diamond

T

Table

Top flat facet of a polished diamond

Table Percentage

Comparison of the size of the table facet to the width of the diamond at the girdle in percentage

Tension

Setting that uses tension to hold a diamond between fine metal

Trilliant, Triangular

Diamond shaped like a triangle

U

Ultraviolet Light

Invisible light waves that can have a positive or negative effect on a diamond's appearance

V

W

White Gold

Gold mixed with white metals such as silver, palladium, or nickel

X

Y

Yellow Gold

Natural color of pure gold usually mixed with other metals (to dilute purity)