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0.30-Carat Blue Nile Signature Round Diamond

4.9 (1376)
Stock number
Price per carat
Carat weight
Sig. Ideal
Length/width ratio
Depth %
Table %
Medium, Faceted
4.35 x 4.31 x 2.66 mm
All of our certified diamonds are backed by our Diamond Price Guarantee. Learn More
Canadian Diamond
Each Canadian diamond purchased from Blue Nile is accompanied by a Canadian diamond certificate stating the cut, rough weight, polished weight and Canadian certification number.

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Your questions or feedback are always welcome at Blue Nile. Join in a conversation with one of our Diamond and Jewelry Consultants to help you make the right decision.

Sample Photo Diamond Diagram Sample Hearts & Arrows Photo Actual Photo - Approx. 10x
Diamond Grading Report

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Canadian Diamond
Each Canadian diamond purchased from Blue Nile is accompanied by a Canadian diamond certificate stating the cut, rough weight, polished weight and Canadian certification number.
About Your Blue Nile Diamond

Diamond Size: 0.3 Carat

The international unit of weight used for measuring diamonds and gemstones, 1 carat is equal to 200 milligrams, or 0.2 grams. A specific measurement of a diamond's weight, carat weight alone may not accurately represent a diamond's visual size. Learn More

We recommend considering carat weight along with two other influential characteristics: the overall dimensions and the cut grade of the diamond.

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.25 Ct. (4.1 mm)
.5 Ct. (5.1 mm)
.75 Ct. (5.8 mm)
1 Ct. (6.4 mm)
1.25 Ct. (6.9 mm)
1.5 Ct. (7.4 mm)
1.75 Ct. (7.8 mm)
2 Ct. + (8.1 mm)
17.9 mm  
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Diamond Selected

Cut: Signature Ideal

Signature Ideal cut: Top 1% of diamond quality - with precise proportions, polish and symmetry - allowing the diamond to reflect even more light than the standard Ideal cut.

Want to learn even more about cut? Learn More

A cut grade is the measure of a diamond's light performance. Cut with proper proportions, light is returned out of the top of the diamond. If it is cut too shallow, light leaks out of the bottom; too deep and it escapes out of the side.

Diamond Cut

Color: F

F color: A "colorless" grade appreciated best set in platinum or white gold. Faint color detectable by a trained gemologist.

Want to learn even more about color? Learn More

  • For the purist, look for a colorless diamond with a grade of D-F for a diamond with no discernible color.
  • For an excellent value in a diamond with little or no noticeable color to the unaided eye, look for a near-colorless grade of G-I
Not Carried At Blue Nile
Blue Nile Diamonds
Noticeable Color

Clarity: SI1

SI1-SI2: Slightly included. Inclusions noticeable at 10x. Best value if eye-clean. SI2 inclusions may be detectable to a keen unaided eye

Want to learn even more about clarity? Learn More

  • Clarity refers to a diamond's relative absence of tiny, natural characteristics known as blemishes and inclusions.
  • Many of these characteristics are microscopic and do not affect a diamond's beauty in any discernible way.
Representative diamond under high magnification.

Diamond Price Guarantee

The Blue Nile Diamond Price Guarantee makes it easy to purchase diamonds with peace of mind. If you find a comparable GIA certified diamond at a lower price, call 1888-565-7641. If the offer meets our qualifications, we'll match the price. There is no comparison when it comes to the value and quality of Blue Nile diamonds.

The following terms and conditions apply to our Diamond Price Guarantee program.

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Blue Nile Diamond Upgrade Program

  • All GIA and AGSL certified diamonds purchased from Blue Nile are eligible.
  • You will receive credit equal to 100% of the original price toward the purchase of a new diamond.
  • The price of your new diamond must be at least twice the price of your original diamond.
  • Your diamond must be in its original condition with the original diamond grading report.
  • Any damage to the original diamond may disqualify the diamond from the diamond upgrade program.

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REVIEWS: Blue Nile Signature Round Diamonds

4.9 average customer rating for Blue Nile Signature Round Diamonds from 1376 reviews
  • (1207)
  • (160)
  • (7)
  • (0)
  • (2)

No sparkle at all on these. Was counseled they were to be great at I color. And signature.

custom engagement ring

, Washington, DC –

Diamond is beautiful, we both love it!

It's a Y-E-S!!! :) she loved the ring!

, Carnegie, Victoria –

The signature round diamond on a Petite Engagement setting exceeded my expectations. The actual ring looks way better than it did on the website's photos. And yes, i mean YES, thats what I got and she loved how classic and elegant it looks. 2 words - Mission Accomplished! :) Thanks Blue Nile, will definitely come back for future diamond purchases!

0.30-Carat Blue Nile Signature Round Diamond