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Diamond Quality Information

GIA Anatomy of a Diamond

The Gemological Institute of America (GIA) is the world's foremost authority on diamond and gemstones. GIA has established the internationally accepted standard for diamond grading on which Costco's standards are based.

Costco offers our members high quality jewellery at an exceptional value. Our team of GIA Graduate Gemologists inspect every diamond to ensure it meets Costco's strict quality standards. We only sell natural and untreated diamonds.

 

Diamonds The 4Cs of Diamond Quality

Every diamond is a miracle of time, place and chance. Like snowflakes, no two are exactly alike.

Until the middle of the twentieth century, there was no agreed upon standard by which diamonds could be judged. GIA created the first and now globally accepted standard for describing diamonds: Colour, Clarity, Cut and Carat Weight. Today, the 4Cs of Diamond Quality is the universal method for assessing the quality of any diamond, anywhere in the world.

 

Diamond Colour & Clarity Guarantee

Clarity

Internally Flawless
Very Very Slightly Included
Very Slightly Inlcluded
Slightly Inlcluded
Inlcluded
 
IF
VVS1VVS2
VS1VS2
SI
I1I2I3
 

Colour

Colouress
Near Colouress
Slightly Tinted
Very Light Yellow
Light Yellow To Fancy Yellow
 
DEF
GHIJ
KLM
NOPQR
STUVWXYZ
 
* All diamonds offered by Costco are VS2clarity or better and Icolour or better based on the Gemological Institute of America grading scale.
 

GIA 4Cs of Diamond Quality

 

GIA Colour Scale

jewellery-color-d
D
jewellery-color-e
E
jewellery-color-f
F
jewellery-color-g
G
jewellery-color-h
H
jewellery-color-i
I
jewellery-color-j
J
jewellery-color-k
K
jewellery-color-l
L
jewellery-color-m
M
jewellery-color-n
N
jewellery-color-o
O
jewellery-color-p
P
jewellery-color-q
Q
jewellery-color-r
R
jewellery-color-s
S
jewellery-color-t
T
jewellery-color-u
U
jewellery-color-v
V
jewellery-color-w
W
jewellery-color-x
X
jewellery-color-y
Y
jewellery-color-z
Z
 
D~F : Colourless G~J : Near Colourless K~M : Faint N~R : Very Light N~R : Light
 

GIA Clarity Scale

jewellery-clarity-flawless
Flawless
jewellery-clarity-internally-flawless
Internally Flawless
jewellery-clarity-vvs1
VVS1
jewellery-clarity-vvs2
VVS2
jewellery-clarity-vs1
VS1
jewellery-clarity-vs2
VS2
jewellery-clarity-si1
SI1
jewellery-clarity-si2
SI2
jewellery-clarity-i1
I1
jewellery-clarity-i2
I2
jewellery-clarity-i3
I3
 
Very Very Slightly Included : VVS1  VVS2 Very Slightly Included : VS1  VS2 Slightly Included : SI1  SI2 Included : I1  I2  I3
 

GIA Cut Scale


Excellent

Very Good

Good

Fair

Poor
 

Carat Weight

jewellery-weight-05
0.50 ctw.
jewellery-weight-1
1.0 ctw.
jewellery-weight-2
2.0 ctw.
jewellery-weight-3
3.0 ctw.
jewellery-weight-4
4.0 ctw.
* All diamond images and diagrams are for reference only and may not reflect true diamond quality grades or carat weight. Images are not for use in diamond grading.
 
 

Certificates

Costco Article of Description - A detailed article of description will accompany diamond items with centre stones less than 1.00ctw.

Gemological Institute of America (GIA) Diamond Grading Report - All items with a 1.00 carat or larger diamond centre stone will include a GIA Diamond Grading Report detailing the centre diamond.

Gemological/jewellery Report - All items with a 1.00 carat or larger diamond centre stone will also include a Gemological/jewellery Report describing the article of jewellery. This report will not have a monetary value listed. You can contact the the company that issued the report and request an insurance appraisal, in which case your Costco purchase price will be documented as the insurance replacement value.

 

Care and Maintenance

Although diamonds are one of the hardest substances on earth, they are still vulnerable to damage such as abrasion, chipping and breakage. We recommend having your jewellery inspected every 6 months by your local qualified jeweler for any needed maintenance or repair, avoid all harsh chemicals, such as chlorine or ammonia, as they may damage the metal and/or stones.