Diamond measurements and size in each diamond shape will vary even at the same carat weight. This is mostly due to the fact that different shape diamonds are cut to different dimensions to maximize their brilliance. This includes length, width and depth. For example, a 1ct round brilliant cut diamond will measure quite differently than a 1ct oval diamond. Often I have customers who want a diamond somewhere between 1.00 carat and 2.00 carats. Here, at deBebians, we do sell certified loose diamonds from 0.30ct all the way up to 10.00 carats. Today I’m going to share with you what 1 carat diamonds will approximately measure in different shapes.
Round: 6.5mm
Princess: 5.5 x 5.5mm
Pear: 8 x 5mm
Marquise: 10 x 5mm
Oval: 7 x 5mm
Emerald: 7 x 5mm
Heart: 6.5 x 6.5mm
Radiant: 6.2 x 5.5mm
Cushion: 5.5 x 5.5mm
Asscher: 5.4 x 5.4mm
*Please note, these diamond shapes are not to scale.
These are just approximate mm sizes for each diamond shape but it gives you a great idea as far as how 1.00ct diamonds will measure. Fancy shapes, such as ovals and pears can give a lot more spread (how the diamond measures face up) and some customers who want a larger looking diamond may prefer shapes like this. Length and width will determine the actual spread of a diamond but the depth of the diamond is very important. As a gemologist, I do feel strongly that you should never sacrifice cut grade to try to get a larger measuring diamond. I have worked with customers who found and wanted to purchase shallow measuring diamonds (meaning a shallow depth percentage) only because the diamond would measure a little larger face up. One customer I had wanted a princess cut diamond. Typically the depth percentage on a princess cut diamond should be around 70%, give or take a little. This diamond had a depth percentage less that 65%. Basically the diamond measured a bit larger in terms of what it should have based on the carat weight but the diamond lacked brilliance and sparkle and overall just wasn’t a pretty diamond…at all. I emailed the customer pictures of the diamond and once he saw what I was talking about, he agreed with me that it wasn’t too good to be true. I always remind customers that nothing is too good to be true (usually) and that sacrificing the diamond cut to get a larger looking diamond will sacrifice the brilliance and sparkle within that diamond.
Please note that this chart is only meant as an approximate guideline. If you need assistance with your loose diamond search, please feel free to contact us and one of our staff GIA graduate gemologists can assist you! We are eager to help guide you through this process and to help you find that perfect loose diamond!