Based on the given text, List some aspects of the pearl.

1.	Pearl is a sparkling and hard object which is produced inside mollusk shell or other shells.
2.	Just like the shells pearls are also composed of calcium carbonate.
3.	The Ideal pearl is perfectly round and smooth, but it can come in different shapes like baroque pearls.
4.	The best quality natural pearls are valued as gemstones.
5.	Since pearls are fine, rare and valuable it has become a metaphor.