Cortez Pearls

Cortez Pearls

Cortez Pearls Defined

Cortez pearls are pearls grown in the Pinctada maxima and Pteria sterna mollusks in the Gulf of California.

The History And Comeback Of Cortez Pearls

Emerging once more from the clear waters of the Gulf of California, after decades of protection, is Mexico’s most emblematic gem: ‘New World Black Pearls’. In 1533, the Spanish Conqueror Hernán Cortez sent the very first expeditions into the area to find the mythical “Sea of Pearls”. Soon, the area known as the “Vermillion Sea of Cortez” – officially known as the Gulf of California - produced some of the finest known pearls in the world: the Sea of Cortez Pearl. These prized gems became New Spain’s most important export product, with a price so high that their value was over double of that of all other combined exports to the Old Continent: gold, silver and spices. It was at this moment in time when Mexican black pearls came to be known as the “Queen of Gems and Gem of Queens”, helping to adorn European nobility like never before.

Cortez Pearls Come From Two Species

Sea of Cortez Pearls originate from two species of mollusks that inhabit the Pacific coastline: the “Panamic Black-Lipped Oyster ” or “Madreperla”, (Pinctada mazatlanica) and the “Rainbow-Lipped Oyster ” or “Concha Nácar”, (Pteria sterna) both capable of producing pearls of incredible beauty. The “Rainbow-Lipped Oyster” produces pearls of highly unusual colorations and intense iridescence, thus producing a pearl that is clearly distinguishable from all others.

Cortez Pearls Were Almost Hunted To Extinction

Because of their demand, the natural pearl beds were fished constantly for pearls and pearl-shell, so in 1939 a permanent fishing ban was imposed in order to save the few remaining pearl oyster populations, ending up a 400-year reign for the Gulf of California black pearl. Nonetheless, this period left a clear mark in the history, culture and traditions of northwestern Mexico: a living history of legends, stories of sadness and glory.

Cultured Production Brings The Comeback Of Cortez Pearls

Nowadays, these cultured pearls are produced in Mexico’s Gulf of California: Bacochibampo Bay, Guaymas, Sonora. Pearl culture began in the region in 1993 as a university research program, but by 1996 a commercial production of 20,000 mabe was achieved. Loose cultured pearl production began in the year 2000. The only marine cultured pearl farm in the Western hemisphere is a medium-sized farm, with some 200 thousand oysters grown in a suspended culture system, with a yearly output of 3-4 kg of cultured pearls, and 5 thousand mabe pearls.

The Culturing Process For Cortez Pearls

The culture process is continuous and has a minimum production term of 4 years: 2 years for the mollusk's grow-out period, and an additional 2 years for the production of cultured pearls. The pearl seeding operation is proprietary, and known only to the original university research team. Each adult, (2 years old, 8 to 10 cm in diameter) Rainbow-Lipped Oyster (Pteria sterna) is seeded with only one American freshwater shell-nucleus, ranging in size from 2.1 to 3.3 bu (6.5 to 10.0 mm) and a piece of mantle tissue from a donor oyster.

Sea of Cortez Cultured Pearl Attributes:

Nacre thickness: is of a minimum of 0.8 mm to a 2.3 mm after the 24 month culture period.

Size: The pearls range in size from 8.0 to 14.0 mm in diameter. Pearls in sizes above 10 mm represent only 5% of a harvest.

Pearl Shape: Baroques make up for the largest yield (71%) while rounds and near-rounds account for only 3%. Semi-Baroque shapes represent 25% of the harvest.

Pearl coloration: Cortez pearls either display an opalescent rainbow-like orient or intense overtones. Body colors range from both warm and cool tones of white, silver-gray, bronze to black, with several overtones of green, purple, blue, gold and violet.

Treatments: The pearls are untreated. After harvest, pearls are soaked in water and pat dried. The Sea of Cortez Pearl (or “Cortez Pearl”) is the only pearl in the gem industry that completely qualifies under the "Fair Trade Gems" protocols.

South Sea Pearls

South Sea Pearls

South Sea Pearls Defined

A South Sea pearl is pearl produced by the Pinctada maxima mollusk. They are currently cultured in areas throughout the Indian and Pacific Oceans, primarily in Australia, the Philippines, Indonesia and Myanmar.

South Sea Pearls – Among The Largest In The World

South Sea pearls are among the largest commercially harvested cultured pearls in the world. The average size of a South Sea pearl is 13 mm, with most harvests producing a range of sizes from 9 mm to 20 mm. The South Seas lie between the northern coast of Australia and the southern coast of China. These waters are the native habitat of a large oyster known as Pinctada maxima. This oyster grows up to 12 inches in diameter, and can be nucleated with a much larger bead than other saltwater oysters such as the akoya.

South Sea Pearls Come From Two Varieties Of Pearl-Producing Mollusks

There are two varieties of Pinctada maxima, the silver-lipped and the gold-lipped. The two are distinguished by their distinct coloration of the outer edge of the interior. This type of shell is also known as mother-of-pearl, and is responsible for the coloration of the cultured pearls produced, therefore the name. Unlike the akoya oyster, the South Sea oyster will only accept one nucleation at a time. The oyster is nucleated when it is only about half developed, from 4.7 inches to 6.7 inches in size, or about 24 months old. Although the South Sea oyster will only handle one nucleus at a time, this oyster (like the Tahitian pearl producing Pinctada margaritifera) can be nucleated up to three times over the course of many years.

Why South Sea Pearls Grow So Large

There are four reasons South Sea pearls can grow to such large sizes, dwarfing many of their other saltwater pearl counterparts. These reasons are: the large size of the Pinctada maxima, the size of the implanted bead, the length of time the pearl is left to grow in the oyster, and the oyster’s environment. Due to the size of the oyster, it is able to accept a large bead. The gonad of the Pinctada maxima is several times larger than that of the akoya. Because of this larger gonad, the South Sea oyster deposits nacre around the nucleus at a much quicker rate, especially in warm water, which speeds the oyster’s metabolism.

The South Seas are also extremely clean, and filled with plankton – the Pinctada maxima's favorite food source. The clean waters and abundant food supply also speeds the nacre production. The growth period for South Sea pearls is also substantially longer than that of the akoya. Akoya pearls are harvested after only 9-16 months, where as South Sea pearls are harvested after a minimum of two years allowing for a larger size.

What Makes South Sea Pearls So Unique

South Sea pearls have several distinct characteristics that are unique to this gem. The nacre is unusually thick, ranging from 2 - 6 mm, compared to the 0.35 - 0.7 mm of an akoya pearl. South Sea pearls have a unique, satiny luster that comes from the rapidly deposited nacre and warm waters of the South Seas. South Sea pearls also have a subtle array of colors; typically white, silver, and golden, that are rare in other pearl types.

Tahitian Pearls

Tahitian Pearls

Tahitian Pearls Defined

Tahitian pearls are bead-nucleated pearls grown in the gonad of the Pinctada margaritifera mollusk in French Polynesia.

Tahitian Pearls – Among The Most Beautiful In The World

Tahitian pearls are produced in the black-lipped oyster ‘Pinctada margaritifera’, in and around Tahiti and the French Polynesian islands. This oyster itself is quite large - sometimes over 12 inches across and weighing as much as 10 pounds - which often results in much larger-than-average pearls. The pearls are unique because of their natural dark colors. Most "black" Tahitian pearls are not actually black, but are instead silver, charcoal, or a multitude of colors with the dominant color being green. Truly black pearls are among the most beautiful pearls in the world, and are extremely rare.

Tahitian Pearls – Not From Tahiti

Although Tahitian pearls are thought by many to be solely a product of Tahiti, this is in fact not true. Tahiti is the commercial center and trading hub for the bulk of the industry, however Tahiti does not have any pearl farms actually located on the island. The farms are instead scattered throughout French Polynesia, as far east as the Gambier Islands, and beyond French Polynesia to the west into the Micronesian Islands. Australia, the Seychelles and Vietnam have all produced black pearls as well, but those cannot be referred to as Tahitian pearls.

Almost Hunted To Extinction

Not only are the pearls beautiful, but the black-lipped oyster's mother-of-pearl inner shell is also extremely attractive. By the early part of the 20th century, before conservation and repopulation efforts began, the oyster had almost been hunted to extinction for its shell alone.

Tahitian Pearl Farming Begins

Tahitian pearl farming has much later commercial origins than its other cultured pearl cousins. In the early 1960's a man by the name of Jean-Marie Domard began experimenting with the ‘Pinctada margaritifera’ using Japanese culturing techniques. In 1962, Mr. Domard successfully nucleated 5,000 oysters, and after 3 years harvested more than 1000 high-quality Tahitian pearls.

Akoya Pearls

Akoya Pearls

Akoya Pearls Defined

Akoya pearls are bead-nucleated cultured pearls produced in the Pinctada fucata martensii and Pinctada fucata chemnitzii primarily in Japan, China, Vietnam, South Korea and Australia.

What Are Akoya Pearls?

Akoya pearls are cultured in the Pinctada fucata martensii, also known as the akoya oyster. This mollusk is found and farmed primarily in Japan and China. Renowned for their luster, akoya are considered the classic pearl. They are generally white or cream colored, with overtone colors of rose, silver, or cream.

Akoya Pearls, The Perfect Pearl For Jewelry

The akoya oyster is the smallest pearl-producing oyster used in pearl culture today, so akoya pearls also tend to be small, ranging in size from about 2 to 11 millimeters. They also tend to be the most consistently round and near-round pearls, making them ideal in terms of matching for multi-pearl jewelry such as strands and bracelets.

Freshwater Pearls

Freshwater Pearls

Freshwater Pearls Defined

Freshwater pearls are pearls which grow in non-saline environment in freshwater mussels.

Where Do Freshwater Pearls Come From?

Although the traditional source of pearls has been saltwater mollusks, freshwater mussels, which live in ponds, lakes and rivers, can also produce pearls. China has harvested freshwater pearls in the form of mabe since the 13th century, and has now become the world's undisputed leader in freshwater pearl production. The first record mentioning pearls in China was from 2206 BC. The United States was also a major source of natural freshwater pearls, from the discovery of the New World, through the 19th century, until over-harvesting and increasing pollution significantly reduced the number of available pearl-forming mussels in the US.

The Appeal of Freshwater Pearls

Generally speaking, freshwater pearls are not as round as saltwater pearls, and they do not have the same sharp luster and shine as akoya pearls. However, they appear in a wide variety of shapes and natural colors, and they tend to be less expensive than saltwater pearls, making them very popular with younger people and designers. Also, because freshwater pearls are solid nacre, they are also quite durable, resisting chipping, wear, and degeneration.

China Leads The World In Freshwater Pearl Production

With a total production of 1,500 tons in 2006, China holds a monopoly over the pearl industry today. Although the birth of the Chinese freshwater pearl industry is traced back to the area around Shanghai, freshwater pearls are now produced in all the surrounding provinces including: Zhejiang, Anhui, Jiangsu, Hubei, Hunan, and Jianxi. Local pearl trade is conducted mainly in the cities of Zhuji (Shanxiahu), Suzhou, Wuxi, Wenling, and Weitang. The largest marketplace for these freshwater pearls is the world's pearl trading hub, Hong Kong.

What Makes Freshwater Pearls Different?

Freshwater pearls differ from other cultured pearls, in that the great majority of them are not bead-nucleated. Freshwater mollusks are nucleated by creating a small incision in the fleshy mantle tissue of a 6 to 12 month old mussel, then inserting a 3mm square piece of mantle tissue from a donor mussel. Upon insertion, the donor, (graft) tissue is twisted slightly, rounding out the edges. What happens after this point is really just speculation. Some believe that this tissue acts as a catalyst in producing a pearl sac thus making the 'nucleation' actual 'activation'. Others believe the tissue molds with the host to create a pearl sac, while still others maintain the tissue is the actual nucleus. Although it is said that a freshwater mollusk can withstand up to 25 insertions per valve, it is common industry practice to perform only 12-16 insertions in either valve, for a total production of 24-32 pearls. The mollusks are then returned to their freshwater environment where they are tended for 2-6 years. The resulting pearls are of solid nacre, but without a bead nucleus to guide the growth process the pearls are rarely perfectly round.

What Makes Today’s Freshwater Pearls So Much Better?

The major increase in quality can be attributed to several factors. The primary jump in quality was accomplished when the industry shifted from the Cockscomb pearl mussel, (Cristaria plicata) to the Triangle shell, (Hyriopsis cumingii) in the middle 1990's. The Cockscomb was responsible for the low-quality rice-crispy pearls of the 1970's and 1980's. Another shift in quality can be attributed to the lower number of grafts inserted into either valve. This number has dropped by an average of 5 per side in the last decade. The turn of the century brought another wave of quality and exotic pearl colors in the form of mussel hybridization.

Japans Freshwater Pearl Industry, A Rough History

The Japanese have a distinguished history of culturing freshwater pearls as well. Lake Biwa was once world renowned for producing high-quality freshwater pearls produced by the Hyriopsis schlegelii, (Biwa pearly mussel) mussel. However, in the mid 1970's pearl farming all but came to a halt due to pollution in this lake that was once synonymous with freshwater pearls. The Japanese tried once again to farm freshwater pearls in Lake Kasumigaura in the last decade, utilizing a bead-nucleated hybrid mussel (Hyriopsis Schlegelii/Hyriopsis cumingii). The resulting pearls have been quite large and unique. The Kasumiga pearl industry had a very short life span, however, with production ceasing in 2006. The industry is once again a pollution fatality of Japanese industry. The remaining Kasumiga pearls are exclusively sold by the Belpearl pearl company.

Saltwater Pearls

Saltwater Pearls

Saltwater Pearls Defined

A saltwater pearl is a pearl produced by a saltwater mollusk in a saline environment.

Traditional Saltwater Pearls

Traditionally, most pearls were gathered from saltwater-dwelling mollusks in the Persian Gulf, the Red Sea and the coastal waters of India and Japan. These saltwater pearls were referred to as marine pearls. Natural saltwater pearls are still found, but the yield is too small to account for any significant market share.

Saltwater Pearls Today

Today, any pearls cultured in mollusks inhabiting saline waters are considered saltwater pearls. The three most common types of saltwater pearls are akoya pearls, Tahitian pearls, and South Sea pearls.

Shape of Saltwater Cultured Pearls

Saltwater cultured pearls tend to be more round than freshwater cultured pearls. This is due to the fact that saltwater mollusks are universally bead nucleated. Unless the saltwater pearl is a keshi pearl, it will have a bead core.

Saltwater Perliculture

Saltwater pearls are cultured by prying open the mollusk 2-3 centimeters. A technician then uses a special instrument to make a minute incision on the gonad (reproductive organ) of the animal. A small bead nucleus is inserted into this hole, and a tiny piece of mantle tissue is then placed behind it. The epithelial cells in this mantle tissue grow around the nucleus producing a pearl sac. This is where the pearl grows. This process is the same for all saltwater pearls cultured today.

Cultured Pearls

Cultured Pearls

Cultured Pearls Defined

A cultured pearl is any pearl grown with the influence of human intervention.

Cultured Pearl Formation

A pearl is formed when a small irritant or parasite penetrates and lodges in the mantle tissue of a mollusk. In response, a substance called nacre is secreted, and the creation of a pearl begins. Nacre is a combination of crystalline and organic substances. The nacre builds up in layers, as it surrounds the irritant to protect the mollusk, and after a few years, this build up of nacre forms a pearl.

Natural Pearls vs. Cultured Pearls

Natural pearls, are pearls formed by chance. Cultured pearls have been given a helping hand by man. Today, nearly all pearls are cultured. By inserting a foreign object into a mollusk, pearl farmers can induce the creation of a pearl. From there, the same process of natural pearl creation takes place. The difference is that in this case, the inducement is intentional.

Cultured pearls can be distinguished from natural pearls through the use of x-rays, which reveal the inner part of the pearl.

The Early Days of Cultured Pearls

Harvesting cultured pearls from the oysterModern-day cultured pearls are the result of discoveries made in the late 19th and early 20th centuries, by Japanese researchers Tatsuhei Mise, Tokishi Nishikawa, and the son of a noodle maker, Kokichi Mikimoto. Although some cultures had long been able to artificially stimulate freshwater mollusks into producing a type of pearl, the pearls produced in this way were generally hemispherical mabes, rather than completely round pearls.

Finally, Producing Round Cultured Pearls

While early on in Mikimoto’s career he focused on mabe production, he eventually produced rounds with a technique involving tissue and bead insertion into the gonad of an akoya mollusk. He patented this technique in 1916.

The Cultured Pearl Industry Is Born

This revolutionized the pearl industry because it allowed the reliable, consistent cultivation of large numbers of quality pearls. The cultured pearl industry of today was born. While natural pearls have widely varying shapes, sizes, and qualities, and are difficult to find, cultured pearls could now be "designed" round from the start. High quality, round pearls could now be produced by the millions; making them available and affordable to everyone.

Today’s Cultured Pearl Industry

The development of pearl culturing took much of the chance, risk, and guesswork out of the pearl industry. It has allowed it to become stable and predictable, fostering rapid growth over the past 100 years. Today, the cultured pearl industry has essentially replaced the natural pearl industry with production of cultured freshwater, South Sea, Tahitian, and of course Mikimoto’s original akoya pearls.