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Diamond Quality Information

General Costco jewellery and Watch Information

Jewellery & Watch Information

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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

VVS₁VVS₂

VS₁VS₂

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

D~F : Colourless G~J : Near Colourless K~M : Faint N~R : Very Light N~R : Light

GIA Clarity Scale

Flawless

Internally Flawless

VVS₁

VVS₂

VS₁

VS₂

SI₁

SI₂

I₁

I₂

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

0.50 ctw.

1.0 ctw.

2.0 ctw.

3.0 ctw.

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.

Diamond Quality Information

GIA Anatomy of a Diamond