Cricle Size Disorting Optical Illusion

This is a unique view of a classic size distortion illusion. Looking at the illusion art below which crystal is larger the one in the center of the top left circle or the crystal in the center of the lower right circle? Each is surrounded by 6 other crystals. At first glance it appears that the crystal in the center of the top left circle is the larger of the two truth is though they are the exact same size.