Cultured pearls are grown in freshwater and saltwater. There are four major types of pearls:
Akoya, Freshwater, South Sea and Tahitian.
Akoya
Akoya pearls are saltwater pearls cultivated in Japan and China. They're the most classic variety of pearl (and the most popular). Most Akoya pearls have a white or cream bodycolor with overtones of rose, cream and silver. Akoya pearls range in size from 2mm to 10mm.
Freshwater
Freshwater pearls are cultured in bodies of freshwater such as lakes and ponds. China and the US are the leading producers. Freshwater pearls occur in the widest variety of colors. Freshwater pearls range in size from 6mm to 8mm.
South Sea
Australia, Indonesia and the Philippines are the leading producers of South Sea saltwater pearls. South Sea pearls are divided into two categories: White South Sea pearls and Golden South Sea pearls. White South Sea pearls have a white bodycolor with overtones of rose and silver. Their silky appearance is outstanding. Golden South Sea pearls range from light champagne to a golden wheat color. South Sea pearls range in size from 8mm to 22mm.
Tahitian
Tahitian saltwater pearls are named after the tropical island of Tahiti; however, they are cultivated in many places around the French Polynesian islands. Tahitian pearls are the only naturally-occurring dark colored pearls. Their color ranges from light gray to dark gray and green with overtones of greens, blues and purple. Tahitian pearls with peacock color, or green-gray to blue-gray body color and pink to purple overtone, are a favorite. Tahitian pearls range in size from 7mm to 20mm.