Blue Zircon Plain Hearts measure approximately 3.5x3.5mm to 5x5mm in a petite size, have a sub-adamantine luster which is just under Diamond for scintillation showing a superior brilliance, an excellent cut with good symmetry, a well matched strand of true blue in a medium light saturation for Zircon, and they are a wonderful example of the best blue Zircon color, and the extra value is that they are a Blue Diamond substitute.