Brilliant (Round)

This is the most popular style of all diamond shapes. It consists of 57 facets, 58 if the culet is also faceted.

Fancy
Any other geometry such as Princess, Pear, Marquise, Emerald, Oval and Heart-shaped.

Facets
The flat, polished surfaces of a diamond.

Table
The top facet.

Girdle
The outer diameter which is the outermost 'edge' of the diamond. The girdle plane is the largest diameter of the diamond.

Crown
The top portion of the diamond, above the girdle.

Pavilion
The bottom portion of the diamond, below the girdle.

Culet
The pointed bottom of the pavilion, sometimes polished with a tiny facet, sometimes pointed with no facet.  It is linear on some shapes such as Emerald cut.

Fluorescence
It is the natural, blue glow of some diamonds under Ultra Violet light.  It is a minor point.  It is a way to differentiate between nearly identical diamonds and to make the 'fingerprint' of the diamond more specific within the certification.  It isn't good or bad, it just "is".  With a diamond that is I or J, some argue that you want strong Fluorescence, because the Fluorescence can mask the 'tint' and make it look slightly whiter.  With a Colorless diamond, it really doesn't matter.  Since Fluorescence occurs under 344 nanometer wavelength light, it really is a minor point and not noticeable under normal conditions, unless you put it under a black light or ultraviolet lighting.

Judging a diamond as "good" or "bad" strictly from the stand point of Fluorescence, is like saying, "I could have bought that Ferrari Testarossa for $5,000... but I didn't like the shape of the gas pedal."  If you put a pair of 1ct, colorless, round earrings together with one diamond having "Strong" and the other having "None/Nil".  You couldn't tell one from the other.  Try it yourself!  Go downtown and have 2 GIA diamonds of the same color/shape, put side by side with differing fluorescence (Strong and None) and see if you can tell a difference.

Polish
The extent to which the surface of the stone is free of scratch or defect under 100x magnification.

Proportion
The size and angle of facets, as they are oriented to each other. A diamond cut to correct proportions will reflect light back through the Table and Crown, where an incorrectly proportioned diamond will lose its brilliance as the light escapes through the bottom, Pavilion 

Color
Color describes the presence or absence of ‘yellow’ in a diamond.

 Color

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Fancy

Scale

Colorless

Near Colorless

Faint Yellow

Very Light Yellow

<------Light Yellow---->

Color

 

Clarity -- Show Chart [+]
Clarity describes the absence of imperfections or “inclusions” and the relative purity of a diamond.

Carat Weight
A diamond’s weight is measured in Carats. Compared to Color and Clarity, the Carat weight is one of the few properties of a diamond that the cutter can control. Generally, as diamond weight increases by 100% (double the weight), the cost of the diamond can increase by 200%.  A .50 ct diamond that will cost $1000, may cost $3000-$4000 if it is a full carat.

Carats to Millimeters Conversion Chart for Round Diamonds -- Show Chart [+]

 



Cut / Proportion
Cut is controlled by the skill of the cutter.  Correct cut has high importance because it affects the brilliance and fire of the diamond. The cut of a diamond is the size and angle of facets in relation to how they are oriented to each other. A diamond which is cut to correct proportions will reflect light back through the Table and Crown (top part of the diamond), where an incorrectly proportioned diamond will lose its brilliance as the light escapes through the Pavilion (bottom of the diamond).