PEARL

Cultured pearls from left to right: Silver South Sea, Akoya, Golden South Sea, Tahitian

Species:  Pearl (or Cultured Pearl)
​​Mohs Hardness:  2.5 to 4.5 out of 10
Color:  Can be almost any color, but usually white or light yellow, and body color can be modified by pink, green or blue overtones.
RI:  1.350 to 1.685 (+0.009 / -0.005)
Birefringence:  0.155 (use birefringence blink method)
SR/DR/AGG:  Too opaque to test
Spectrum:  Not diagnostic
Fluorescence:  Varies.  Inert to strong light blue, yellow, green or pink under LW and SW.
SG:  Saltwater - 2.61 to 2.85, Freshwater - 2.66 to 2.78 (few over 2.74)

SHOP PEARL JEWELRY

Pearl Facts

Pearls come in many shapes, sizes and colors.

​Pearls are organic gems created by various oysters, clams and snails.

Natural pearls form around microscopic irritants in the bodies of certain mollusks and marine snails.  Natural pearls are very rare and can be extremely valuable.

In 1893, Kokichi Mikimoto successfully cultured a pearl in Japan.
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Nearly all pearls in today's jewelry is cultured.  The pearl culturing process involves surgically inserting multiple bead nuclei into the tissue of certain mollusks.  The mollusk instinctually coats the beads with layers of nacre as a defense mechanism, over time producing a pearl.

Most oysters take 12 to 18 months to produce a pearl.

Pearls display a unique phenomena known as "orient".

There are several different types of pearls:  akoya, South Sea, Tahitian, freshwater, conch, quahog, Tridacna & more!

​Pearls have been coveted for thousands of years.  A Chinese historian recorded the oldest mention of natural pearls in 2206 BC.​​

Pearls' quality and value are determined based upon the following factors:  size, shape, color, luster, surface quality, nacre quality, and matching (if on a strand).​

Pearl is a June birthstone and is the 3rd & 30th wedding anniversary gemstone.

Pearl Types

ABALONE PEARL (NATURAL OR CULTURED)

Abalones are small to very large marine gastropods from the Haliotidae family.

Abalone snails can be found in Australia, Japan, the United States, New Zealand and South Africa.

Many abalone pearls are natural, although they can be cultured.

Abalone pearl colors can be highly-iridescent silver or green with flashes of nearly every color of the rainbow!

AKOYA PEARL (CULTURED)

Akoya pearls are created by the marine mollusk from the Pteriidae family, known as the Pinctada fucata.

Akoyas are the most popular type of pearl found in jewelry.

Nearly all akoya pearls are cultured.

They typically range from 2mm to 11mm in diameter.

Usually spherical or off-round but can also be oval, pear, baroque, or button-shaped.

Akoya pearls' natural colors generally range from white to yellowish, to light pink.

Akoya pearls are cultured in Japan, Australia, China, Hong Kong, Korea & Sri Lanka.

CONCH PEARL (NATURAL)

A conch is a medium to large-sized marine snail from the Strombidae family, known as the Strombus Gigas, or Queen Conch.

Queen Conchs are found off the coast of the Bahamas, Florida Keys, Caribbean Islands and Bermuda where they're harvested for their delicious meat.  Popular conch dishes include conch fritters, conch salad and conch chowder.

Very rarely, a natural pearl will be found inside a conch shell.

Only 1 out of every 10,000 to 15,000 conchs will produce a pearl.

Only 1 out of every 100,000 to 150,000 conchs will produce a gem conch pearl!

These natural conch pearls are created when an irritant, such as a grain of sand, enters the mollusk.  As a defense mechanism, the conch will coat the irritant with a calcium carbonate, over time producing a porcelain-like pearl.

Conch pearls can range in color from pink to red, orange, brown and white, sometimes displaying a characteristic known as flame structure that appears as a fire burning on the pearl's surface.  This flame-like or silk-like appearance is due to a phenomena known as chatoyancy​.

It's unusual for a conch pearl to exceed 3mm in diameter.  Conch pearls over 10mm are considered exceptionally rare.

FRESHWATER PEARL (CULTURED)

Most freshwater pearls are created by the Hyriopsis Cumingi, or triangle shell mussel.

Nearly all freshwater pearls are cultured.

Unlike saltwater pearls, which are bead-nucleated, older freshwater pearls were mantle-nucleated.  Meaning the mussels were implanted with tissue from donor mussels, generally resulting in less-round pearls.

However, more recently freshwater pearls have been cultured with mother-of-pearl bead nuclei, resulting in larger, more round pearls that can even resemble cultured South Sea pearls.

Freshwater pearls are cultured almost exclusively in China, but are also farmed in Japan and the United States in limited quantities.

While saltwater oysters create 1 pearl at a time, freshwater mussels can create up to 50 pearls at once.

Freshwater pearls can be nearly any shape including round, near round, drop, button-shaped, oval and baroque.

They can range in size from 1mm seed pearls to over 20mm in diameter.

Colors can range from white to cream, lavender or pink.

KESHI PEARL

​What are keshi pearls?

Are they natural or are they cultured?

Well, they're a little bit of both!

Keshi pearls are not cultured, but are a byproduct of the culturing process.

Like natural pearls, keshi pearls are non-nucleated.  This means they are made entirely of nacre.

Keshi pearls can have very strong orient (multi-colored, iridescent overtones).

Keshi pearls can occur in both saltwater mollusks and freshwater mussels.

Keshi pearls are usually caused by a mishap in the culturing process where the grafted mantle tissue separates from the nucleus.

MELO MELO PEARL (NATURAL)

Melo pearls are amongst the rarest gems in the world.

They're created by the Indian Volute, or Melo Melo:  an extremely large marine gastropod from the Volutidae family, found in Southeastern Asian waters.

These large melo snails inhabit shallow waters off the coast of Myanmar, Thailand, Cambodia, Vietnam, Malaysia, the Philippines and the South China Sea.

The finest melo pearls are an intense orange color with visible flame structure.  This flame-like or silk-like appearance is due to a phenomena known as chatoyancy​.

Melo pearls can range in size from just a couple millimeters to over 30mm in diameter!  The largest recorded melo pearl weighs just under 400 carats!  (397.52 cts.)

QUAHOG PEARL (NATURAL)

​​Quahog pearls (pronounced KO-hog) are very rare, organic gems created naturally by the bivalve clam, Venus mercenaria or Mercenaria mercenaria.

Quahog pearls are found by fishermen off the eastern coast of the United States, typically in the New England region, where clams are harvested for their delicious meat for use in popular dishes such as clam chowder. 

It is estimated that only 1 out of every 100,000 quahog clams will produce a pearl of any kind.

Purple and lavender are considered to be the most valuable shades of quahog pearls.

In 2015, a 6-plus carat lavender Quahog pearl was found by a policeman while eating a seafood soup.  This pearl received national media attention and wound up selling at Kaminski Auctions for $16,500.00.

SCALLOP PEARL (NATURAL)

Scallop pearls are very rare, organic gems created by bivalve mollusks from the Pectinidae family, known as the Atlantic Sea Scallop or the Pacific Lion's Paw Scallop (a.k.a. Mano de León).

Scallop pearls are found in shallow waters off the coast of North, Central and South America.

They are non-nacreous, much like conch, melo melo and tridacna pearls.

Scallop pearls can display a phenomena known as aventurescence, which is a glittery appearance caused by light reflecting off of tiny platelets.

Colors range from purple to maroon, orange, brown, and white.

SEED PEARL (NATURAL)

​Seed pearls are non-nucleated, natural byproducts of the pearl culturing process.

They can form in both freshwater mussels and saltwater oysters.

Seed pearls are usually 2mm or less, in diameter.

SOUTH SEA PEARL (CULTURED)

South Sea pearls are organic gems created by the bivalve marine mollusk from the Pteriidae family, known as the Pinctada maxima.

Nearly all South Sea pearls are cultured.

The Pinctada maxima oyster occurs in 2 different varieties:  white-lipped and gold-lipped, producing white, cream, silver, golden, gray, yellow or pink pearls.

South Sea pearls can range from 9mm to 20mm in diameter (typically 10-15mm).

While most oysters take 12 to 18 months to produce a pearl, the silver-lipped oyster takes anywhere between 2 to 4 years to produce a pearl.  This additional time allows for a pearl with a thicker, and more lustrous layer of nacre.

Can be spherical, button, oval, drop or baroque (sometimes circled).
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South Sea pearls are currently cultured in the Indo-Pacific region, including Indonesia, Myanmar, Australia and the Philippines.

TAHITIAN PEARL (CULTURED)

Tahitian pearls are created by the large marine mollusk from the Pteriidae family, known as the Pinctada margaritifera, or Black Lipped Oyster.

Nearly all Tahitian pearls are cultured.

​Generally range from 8mm to 14mm in diameter.
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Usually spherical or off-round but can be oval, pear, baroque or button-shaped.​

Most "black" pearls are actually a charcoal grey, dark green or silver.  True black pearls are rare and can be very valuable.

Tahitian pearls can have overtones of green, rosé, silver, blue, yellow, or any combination of these colors.

TRIDACNA PEARL (NATURAL)

Tridacna pearls are very rare, organic gems created by the largest living bivalve mollusk from the Cardiidae family, known as the Tridacna gigas or Giant Clam.

Tridacna clams can live for up to 100 years, can grow as large as 4 feet across and weigh up to 440 pounds.

Natural Tridacna pearls are known for their porcelain-like white color, sometimes with beautiful flame patterning.

Tridacna clams can be found in the shallow waters of the Indo-Pacific, inhabiting coral reefs.

Previously the largest pearl in history was a Tridacna pearl known as The Pearl of Allah.  It was found off the coast of the Philippines in 1934.  It measures 9.4 inches long and weighs approximately 14 pounds!  This pearl was valued by the San Francisco Gem Laboratory at $40,000,000.00.

The record was broken in 2016 by another Tridacna pearl found in the Philippines.  This massive pearl measures over 2 feet long by 1 foot wide and weighs approximately 75 pounds!

Pearl Videos

All photos and videos are courtesy of Scott Papper, GG, ASA, CMA, RGA, AJP, CSMP, CSSP