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Diamonds

Simplified

Diamond Grading Chart

The Four C's of Quality
by
Vaughn Aubuchon
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This simplified evaluation chart of diamond quality, summarizes "The 4 Cs" of diamond quality grading, which determine value.
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The chart summarizes the evaluation factors of Carat, Cut, Color, and Clarity, and lists the other factors that determine a diamond's value.
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The "Four Cs"
of Diamond Value


Gemological Institute of America
Summary of G.I.A. Standards

1. CARAT

The carat is a unit of weight.
One metric carat consists of 100 "points".
One metric carat = 1/5 gram,
    or 200 milligrams

As the size of a diamond goes up,
     the price goes up exponentially.
Prices can range from $2,000
     up to $60,000 per carat.

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2. CUT

Type of Cut

1. Round - Also called Brilliant,
    the most preferred cut
2. Princess - Square cut,
    second most preferred

Other Cuts:
- Baguette cut (trapezoid)
- Emerald cut (octagon step cut)
- Heart cut
- Marquise cut (pointed oval)
- Oval cut
- Pear-shaped cut
- Rectangle cut
- Square (step cut)
- Trillion cut

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3. COLOR

$$$$$ - $$$$ - $$$ - $$ - $ ----->

G.I.A. Scale:
D, E, F
, G, H, I, J, K, L, M, N, O,
P, Q, R, S, T, U, V, W, X, Y, Z

D, E, F ----- Colorless (most valued)
G, H, I, J --- Nearly colorless
K, L, M ----- Faint yellow
N, O, P, Q, R - Very light yellow
S, T, U, V ---- Light yellow

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4. CLARITY

$$$$$ - $$$$ - $$$ - $$ - $ ----->

GIA Scale:
F
, IF, VVS1, VVS2, VS1, VS2,
S1, S2, S3, I1, I2, I3

F (flawless) is best,
followed by
Internally Flawless,
followed by
Very, Very Small Inclusions
(2 grades)
followed by
Very Small Inclusions (2 grades)
Small Inclusions (3 grades),
Imperfect (3 grades)

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290 - 450

130




Other Important
Diamond Quality Factors

In addition to "The 4 C's" of diamonds, other important factors that determine a diamond's value are:

Culet (the very small face on the bottom)
E- Excellent, VG- Very Good, G- Good, F- Fair, P- Poor

Depth Percentage

Finish -
E- Excellent, VG- Very Good, G- Good, F- Fair, - Poor

Fluorescence

Measurements

Polish -
E- Excellent, VG- Very Good, G- Good, F- Fair, P- Poor


Proportion

Symmetry -
E- Excellent, VG- Very Good, G- Good, F- Fair, P- Poor

Table percentage


Measurements:
Crown Angle - 25-43°
Crown Height
Culet Size
Diameter
Girdle Thinkness - 50-95%
Pavilion Angle - 39-44°
Pavilion Depth
Star Length - 40-70%
Table Depth
Table Size - 50-70%

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370 - 450

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This Vaughns Diamonds Grading Chart
was last updated on 2020-05-05.