South Sea cultured pearls are principally produced in which countries?

South Sea cultured pearls are primarily harvested from two types of oysters known for their size and the quality of pearls they produce, specifically the Pinctada maxima oyster. This species thrives in the warm waters of the southern hemisphere, which is the reason why Australia, Indonesia, and the Philippines are the principal countries associated with South Sea cultured pearl production.

Australia is renowned for its large and lustrous white and golden South Sea pearls, which are highly valued in the global market. The northern coastal waters of Australia provide ideal conditions for these oysters to flourish. Likewise, Indonesia and the Philippines also contribute significantly, cultivating a variety of South Sea pearls in their respective coastal areas.

In contrast, the other options list countries that are either known for different types of pearls or do not have the same prominence in the South Sea cultured pearl industry. For instance, Japan is more well-known for its Akoya pearls, while countries like India and Sri Lanka have lesser involvement in the South Sea pearl sector. Overall, the geographic and environmental conditions of Australia, Indonesia, and the Philippines align perfectly with the cultivation needs of South Sea pearls, making this answer the most accurate.