The most expensive type of pearl can vary based on factors such as size, luster, surface quality, color, and overall rarity. Generally, South Sea pearls and certain varieties of natural pearls are considered among the most expensive:

• South Sea pearls are often regarded as some of the most expensive pearls. They are produced by the Pinctada maxima oyster in the South Pacific, including regions such as Australia, Indonesia, and the Philippines.
• South Sea pearls are known for their large size, ranging from 10mm to 20mm or even larger.
• The cultivation process for South Sea pearls is more delicate and time-consuming compared to some other types of pearls, contributing to their rarity and value.
• Colors can range from white and silver to golden and deep golden.

• Tahitian pearls, produced by the black-lipped oyster (Pinctada margaritifera) in French Polynesia, are known for their unique dark colors, including black, gray, green, blue, and purple.
• The distinctive and vibrant colors of Tahitian pearls contribute to their desirability and higher value.

• Natural pearls, formed without human intervention, are extremely rare and can command exceptionally high prices.
• The rarity of natural pearls, along with their historical significance, contributes to their exclusivity and value.
• Natural pearls come in various shapes, sizes, and colors.