The ancient Chronicle of Mahavamsa mentions the thriving pearl industry in the port of Oruwella in the Gulf of Mannar, Sri Lanka. It also records that eight varieties of pearls accompanied Prince Vijaya’s embassy to King of Pandyan, as well as King Devanampiya Tissa’s embassy to Emperor Ashoka.   Pliny the Elder (23-79 AD) praised the Gulf pearl fishing as the most productive in the world.   
For thousands of years, seawater pearls have been recovered by divers in the Indian Ocean in areas such as the Persian Gulf, the Red Sea and the Gulf of Mannar.    Evidence also suggests a prehistoric origin for pearl diving in these regions.
  Beginning in the Han Dynasty (206 BC-220 AD), the Chinese extensively searched for seawater pearls in the South China Sea.  The 12th century China’s Tanka pearl divers were attached with ropes around their waists so that they could return to the surface safely. 
When the Spanish conquistadors arrived in the Western Hemisphere, they discovered that around the islands of Cubagua and Margarita, about 200 km north of the Venezuelan coast, there was a large pearl bed (a pearl oyster bed). A discovered and named pearl, the La Peregrina pearl, was offered to Philip II of Spain and later given to his wife María I of England.  According to Garcilasso de la Vega, who claims to have seen La Peregrina in Seville in 1607,  was found in Panama in 1560 by a slave who was rewarded with his freedom, and his owner with the post of mayor of Panama. .
Daisy pearls are extremely difficult to find today and are known for their unique yellowish color. Before the turn of the 20th century, pearl hunting was the most common way to collect pearls. Divers manually extracted the oysters from the ocean and river beds and examined them individually for pearls. Not all mussels and oysters produce pearls. In a three-ton cast, just three or four oysters will produce perfect pearls. [Citation required]
Pearls were one of the attractions that attracted Julius Caesar to Great Britain.  They are, for the most part, freshwater pearls of mussels. Pearl fishing was banned in the UK in 1998 due to the endangered state of river mussels.  The discovery and publicity about the sale of the Abernethy pearl in the River Tay for a substantial sum had led to an intense exploitation of the mussel colonies during the 1970s and 1980s by late warriors.  When permitted, it was mainly conducted by Scottish travelers  who found pearls that varied from river to river, the Oykel River in the Highlands was known for the finest pink pearls.  There are two companies in Scotland which are licensed to sell freshwater pearls prior to 1998. 
Cultivation of pearls
Today, commercially grown pearls can be divided into two categories. The first category includes cultured pearls with beads, including those from Akoya, South Seas and Tahiti. These pearls are grown with the gonads and usually one pearl is grown at a time. This limits the number of pearls in a harvest period. Pearls are generally harvested after one year for akoya, 2-4 years for Tahiti and the South Sea, and 2-7 years for fresh water. This pearl farming process was first developed by British biologist William Saville-Kent, who passed the information on to Tatsuhei Mise and Tokichi Nishikawa from Japan. The second category includes freshwater cultured pearls without pearls, such as Biwa or Chinese pearls. As they grow into the mantle, where up to 25 grafts can be implanted in each wing, these pearls are much more frequent and completely saturate the market. There has been a noticeable improvement in quality in ten years when the ancient rice grain-shaped pebbles are compared to today’s nearly round pearls. Subsequently, large nucleated pearls were produced with nearly perfect round pearls up to 15mm in diameter with metallic luster.