The cut of a diamond refers to the quality of light retention and light return – in layman terms, it determines how sparkly a diamond is. If a diamond has a poor cut, the stone will reflect light in ways that don’t send the light back out through the top of the stone. This makes the stone look dull and limits the appearance of sparkle to the human eye. Sometimes this is due to the diamond being too deep or too shallow like we saw in the discussion above. Sometimes it’s the result of other cuts like the table being off center or the girdle being too thick. All of the angles and sizes below directly impact the appearance of the diamond.
The GIA grades diamond cut on a scale from poor to excellent. Excellent cut is by far the most popular cut searched by online shoppers and with good reason. Stepping up from very good (the second best cut) to excellent has a very small impact on the price of a diamond but can have a significant effect on the appearance of the stone. In fact, excellent cut paired with one of the better grades of clarity can make a diamond appear whiter than its grading otherwise implies.
We highly recommend you search for only excellent cut round diamonds, in fact we only show triple excellent round diamonds on our search feature at StoneAlgo. For fancy cut diamonds like cushion or princess cut we recommend staying in the very good or excellent range, which is why we display these cuts on StoneAlgo. The cut is still very important but makes less of an impact in the fancy shapes, not to mention there are far less fancy shaped than round shaped stones so expanding the minimum cut grade broadens your options.
There are a lot of moving parts but generally speaking we try to maximize carat size for our given budget by sticking to the lower end of the color ranges we specified and searching for VS2 or better diamonds. SI1 diamonds are great if they’re eye clean, but they are a pain to find and often end up costing just as much as a VS2 diamond would. If you need one-on-one advice, we offer free support to all our users – simply drop us a line at firstname.lastname@example.org