Color : White, pink, peach, lavender, plum, purple.
Hardness : 3 to 7

Most pearls today in the market are cultured pearls, because of scarcity of natural pearls. A natural pearl starts to form as a foreign object, such as a sea parasite or piece of shell that accidentally lodges itself in an oyster's soft inner body where it cannot be expelled. To rid itself from this irritant, the oyster begins to secrete a smooth, hard crystalline substance around the irritant. This substance is called "nacre." As long as the irritant remains within its body, the oyster will continue to secrete nacre around it, layer upon layer. The final lustrous pearl is the result of this continuous coating process.