Oval Diamond Buying Guide

The Nitty Gritty

Oval-Cut Diamonds give a beautiful sparkle and style.  It’s recommended you choose an H color to be on the safe side and Si1 clarity.  Occasionally you can find an SI2 that looks great but it’s not too common.  The length to width ratio is equally important to ensure you have a classic oval shape.

One must evaluate an Oval diamond closely as it’s not as simple as a round.  GIA doesn’t classify cut grades for any shape other than round.  You will have to analyze the stone with other criteria.

Take a look and click on this link to view an oval diamond that has the same 4 C’s but has a drastic difference in cut and look.  Stone A    vs  Stone B   You can see the shape of the diamond is the most important feature, not the traditional 4C’s. 

Click The Photo To Inspect The Diamond

By clicking on the diamonds, you can see the price differences. This is a perfect example of how shape/cut is valued.  Another important diamond lesson is sometimes when a diamond is discounted heavily there is a reason.  ALways!  


Study your diamond closely or contact me to review your selection before purchase.

The Oval Cut Diamond Buying Guide 

As mentioned above, the shape is critical in buying your oval diamond.  Lets analyze the photo samples from above a little more closely.   A key factor in shape is the length to width ratio. 

Lenght To Width Ratio

Oval diamonds are considered ideal in the 1.35- 1.50 length to width ratio. Most sites do the calculation for you but it’s achieved by dividing the length of the diamond with the width.  View the photo sample below for a detailed break down of its l/w ratio.

oval diamond buying guide


As you can see, even though the carat weight is the same, you gain over 1 millimeter in size by having an ideal L/W ratio.  As an example, you would have to increase your carat size by over .60 to gain another 1 millimeter.  Don’t go to far above the 1.50 ratio or you will have a skinny looking stone that will affect the brilliance.  Also, avoid stones under the 1.35 L/W ration, it will look stubby. 

This comes down to personal preference if one prefers a rounder or longer look.  Here is a link to show you examples of finished rings. Use this to compare what a rounder or longer Oval Diamond looks like mounted. 



Oval Diamond engagement rings

Oval Diamond cut grade 

As I have stated in previous articles, the “Cut” is king and there is no exception here. Oval diamond presents a problem because GIA does not give it a cut grade.   Due to the oval shapes complicated structure, there is no ideal standard.  Too many variables are at play between various length, width and depth combinations, getting an ideal table and crown angle is difficult. 

With that said, there is no ideal combinations so you must take this advice as a general rule of thumb.  Below are guidelines to follow that leads you in the right direction. 

Oval Cut Diamond Cut Guidelines 

Table % 53-63 52 or 64-65 51 or 66-68
Depth % 58-62 56-58 or 62-66 53-56 or 66-71
Girdle Very Thin - Slightly Thick​ Very Thin - Slightly Thick​ Very Thin - Thick​
None Very Small Click Here to view Ideal Pear Small
Lenght To Width Ratio 1.35-1.50 1.30-1.35 or 1.50-1.55 1.25-1.30 or 1.55-1.60


Bowtie Effect 

A big tip in this Oval Diamond Buying Guide is understanding the bowtie effect.  All Ovals will have it with degrees of variance.  With a strong bowtie, You will see a dark effect sketching from the top to the bottom middle. It can be very visible or barely noticeable.  You want to avoid the strong effect as it will affect the brilliance of the diamond.   Feel free to reach out to me if you need any advice with a selection of yours.  

Below you will see a photo example of a bad and great bowtie.  

Oval Bowtie effect

Click on the buttons to show diamond bowtie examples


The color scale by GIA starts at the letter D to Z.  D represents colorless and Z means there is a very noticeable brown and yellow color.  Color originates from the bottom tip of the diamond typically making it harder from the top view to see color.  


It’s very difficult to see the difference between 2 neighboring color grades and generally recommend to stick to H color or better for Oval Diamonds.   This is a perfect balance between quality and price and ensures that you have a diamond that radiates white.  If you set your diamond in yellow or rose gold feel free to lower your diamond color to a J or K color to save money or increase carat size.  

As an example, look at this J color diamond on a yellow gold ring.  

If you want to ensure you have found the right diamond, reach out to me and I will be happy to help. 


There are many grades given to diamonds. Below is a chart outlines them

Diamond Clarity


Most diamonds sold fall under the I1 grade and vvs1.  I consider this the least important C.  A diamond that is flawless and a diamond that’s an eye clean SI1 is indistinguishable to the human eye. SO WHY pay such a high premium for a flawless. 


Here is an example of an incredible SI1 that is almost perfectly clean magnified online and will be eye-clean to the human eye.  IS it easy for you to see a flaw?

Is it worth spending an additional $2,400 by buying This VVS1 diamond?   I try my hardest to have my clients avoid overspending and using that money to upgrade carat size, color, or engagement ring.  That’s money better spent where your eye can actually see a difference. 


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