You need to be wary about the bow tie effect when purchasing pear cut diamond rings. The distinctive shape of a pear cut diamond must facilitate good internal reflection, which in turn contributes to the sparkle of the diamond. The presence of bow tie effect on a major scale can cause a certain portion of the diamond to appear dark. However, having a pear cut diamond with slight bow-tie effect is actually good as it can add to its appearance. Diamonds with severe bow tie effect should be avoided at all costs to ensure that your diamonds are free of such visual phenomena. You can always opt for pear cut diamonds engagement rings that come with a certification from reliable sources like the GIA. Such certification  guarantees that the diamond ring is free from any optical inclusions. Other parameters of a pear cut diamond such as its color, clarity, and length to width ratio all influences the bow tie effect.