What makes a pearl perfect?
Pearls can never be absolutely flawless but the quality and price of a pearl are usually determined by the following criteria:

Shape: Pearls come in eight different shapes (round, drop, oval, button etc.) that are sorted into three types: spherical (rarest and most expensive), symmetrical, and baroque.

Size: This is more of an individual preference and also depends on the type of jewellery. However, larger pearls are rarer and hence more expensive. The largest pearl in the world ¿ Pearl of Lao Tzu ¿ weighs more than 6 kilos and is valued at US$42 million!

Shine and lustre: This is the most crucial assessment factor for pearls. A good quality pearl will have a glow which indicates how well light is reflected from the core of the pearl. The best pearls have an overtone and enveloping ¿mist¿. It also has an orient or the ability to show rainbow colours when rotated under light.
 
Surface quality: A good quality pearl will have very few blemishes, cracks, dimples or bumps. The surface should look clean and feel smooth to the touch. However, pearls often have bubbles or minute, barely there abrasions on their surface that give each pearl a distinct look without adversely affecting its quality or value.