Take a careful look at the following idealscope image:
(This image is copyright of Whiteflash, used with permission.)
There are two hotspots near the base of the arrows between the 3 and 4 o’clock position that are larger than the rest. This is indicative that there will be one smaller heart in the H&A patterning and once you are aware of this, you will also be able to see the difference in the contrast pattern of the diamond.
(This image is copyright of Whiteflash, used with permission.)
If you look carefully, the diamond has been rotated such that the larger pair of hotspots are between the 6 and 7 o’clock arrows.
(This image is copyright of Whiteflash, used with permission.)
You can see that the smaller heart I am talking about is now between the 11 and 12 o’clock position.
Although a smaller heart may not have a huge impact on the light performance of a diamond, it is considered a major flaw in terms of hearts and arrows patterning. There are also more minor flaws that would cause a diamond to miss the mark of a true H&A so just bear this in mind when purchasing a near-H&A diamond.