Diamond Education

The 4Cs of Diamonds

This short tutorial explains the Four C's- cut, colour, clarity, and carat weight - the most important characteristics of buying a diamond.


The cut of a diamond determines its brilliance. Put simply, the better a diamond is cut, the more sparkle it will have.

Learn More About Cut


A diamond's colour grade refers to the lack of colour. The more colourless the diamond, the higher quality grade it will receive.

Learn More About Colour


Almost all diamonds have tiny imperfections. Diamonds with few or no imperfections receive the highest clarity grades.

Learn More About Clarity


This is the term with which people are most familiar, but bear in mind that carat is specifically a measure of a diamond's weight.

Learn More About Carat


Shape describes a diamond's form, mostly from a top view, and all shapes (round, princess, radiant, etc.) have different attributes.

Learn More About Shape


Unbiased diamond grading reports are offered with every Blue Nile diamond.

Learn More About Certification


For most people, buying a diamond is a new experience, but that doesn't mean it should be overwhelming. Understanding a diamond's quality characteristics is straightforward and simple.

Our quality standards are among the highest of all jewellers. As the largest online diamond retailer, Blue Nile offers the largest collection of the world's finest cut diamonds. Pre-selected for exceptional quality, the cut, colour, and clarity of our loose diamonds are evaluated based on a standardized grading scale. Also, each loose diamond is accompanied by a grading report from either GIA, AGSL, independent diamond grading labs with the most stringent grading scales of all labs.

Blue Nile Standards Chart

What Are Other Customers Choosing?

Visit our recently purchased rings and see the engagement rings and diamonds other customers have recently chosen

Truly Zac Posen Vintage Three-Stone Diamond Engagement Ring in 14k White Gold (1/2 ct. tw.)

View Setting

NZ$ 2,500.00

Round 1.18 ct. Diamond

Colour: GClarity: VVS2Cut: Ideal

Find Similar Diamonds

NZ$ 8,852.00

Luna Diamond Engagement Ring in Platinum (1/2 ct. tw.)

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NZ$ 2,500.00

Round 1.18 ct. Diamond

Colour: HClarity: VS1Cut: Ideal

Find Similar Diamonds

NZ$ 9,117.00

Classic Six-Claw Solitaire Engagement Ring in Platinum

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NZ$ 915.00

Round 0.94 ct. Diamond

Colour: IClarity: VS1Cut: Ideal

Find Similar Diamonds

NZ$ 6,935.00

Riviera Pavé Diamond Engagement Ring in 14k White Gold (1/6 ct. tw.)

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NZ$ 1,110.00

Round 0.90 ct. Diamond

Colour: FClarity: VS1Cut: Ideal

Find Similar Diamonds

NZ$ 6,879.00


Find answers to frequently asked questions about diamonds.



Read our tips and hints for finding the perfect diamond.

View Diamond Tips


Read how to keep your diamond sparkling, and securely set in your ring.

Learn About Diamond Care