How Long Does It Take for a Pearl to Form?

Are you diving to find your own pearls? Or simply interested in growing them yourself? I was wondering the same things, so I took the time to research all about how pearls form, and how you can actually grow your own pearls.

How Long Does It Take for a Pearl to Form? It takes at least 6 months for a pearl to form. However, pearls are typically left for at least a year to grow to a decent size.

Pearls can be harvested as early as 6 months in, but the longer the pearls are cultivated, the greater the chances of harvesting a large, high-quality pearl. Freshwater pearls are usually cultivated for 18-24 months before harvesting.

Freshwater pearl takes less time to develop because the layers of nacre (which is what forms a pearl) are not as compact as those surrounding saltwater pearls. But, they can grow just as big.

Do All Oysters Have Pearls?

Any oyster, clam, or mussel has the potential to form a pearl naturally, though some are more common in some species than others.

They all have a mollusk, which creates a material of a pearl. Larger oysters may have a slightly higher chance to have pearls in them, as they are older and had more time to create a pearl.

pearl inside a clam

Unfortunately, there is no obvious sign to know if a pearl is inside an oyster, mussel, or clam – you’ll have to open it to see.

If you’re thinking of going diving and trying to find your own oyster with a pearl in it, then keep reading. The odds of you finding a pearl are very rare.

How Rare is It to Find a Pearl in an Oyster?

Natural pearls are very rare to find. In fact, only 1 in 10,000 wild oysters will have a pearl, let alone the jewelry-graded ones.

Most pearls that you see in the world are cultured pearls, created by farming, like this Akoya cultured pearl necklace.

Natural pearls, created without human intervention, are extremely rare to find. Today, pearls are cultured in pearl farms, and it takes usually a few years before a pearl is created.

How Are Pearls Made?

Pearls can form naturally inside oysters, or they can be cultured or farmed.

Natural pearls from inside oysters, mussels, or clams when a small object (usually a parasite) finds its way inside it.

Then, as a defense mechanism, the oyster will coat the object with fluid, layer by layer which is called “nacre”. Over time, layers of nacre build up and create a pearl. This process can take a long time, as the nacre grows slowly over time.

Cultured pearls are formed the same way, except the farmer carefully implants a piece of mantle tissue, bead or shell inside an oyster. This bead is called “Mother of Pearl“.

Most saltwater cultured pearls are grown with beads.

The growth rate of nacre varies depending on the type of pearl. For Akoya pearls, it grows around 0.3mm per year, for Tahitian and Australian South Sea pearls it’s 2mm per year, up to 5mm per year for Chinese freshwater pearls.

It is sometimes thought that the pearl is formed by the grain of sand, but this is a common myth. Pearls are not formed around grains of sand, but either by the parasite or by a farmer placing a piece of mantle tissue or a bead inside it.

Both freshwater and saltwater pearls are usually round shapes, but they can be of various shapes, and some of the most unusual ones are highly prized for jewelry. Surprisingly, they come in different colors – not just white – but also gray, blue, red, green, pink, and even black.

How Are Pearls Harvested?

Growing your own pearls is a complex procedure, and takes a long time for a pearl to form, but the end result is worth it. They are beautiful to look at and quite expensive.

Pearls are harvested by carefully implanting a small piece of mantle tissue, into the oyster. Pearl farmers may also add a bead, usually from a freshwater mussel to help provide a nucleus for the pearl. After that, the nacre starts forming in 1-3 months.

The speed of nacre forming is different depending on the type of mollusk (which creates the material for the pearl), temperature, and water cleanliness. Pearl must be inspected regularly to check for sickness and to monitor environmental factors such as water quality, temperature, and food quality for the oyster.

Harvesting a pearl does not kill the oyster, and pearl farmers are extremely careful when placing a mantle or bead inside it, as not to harm their oysters.

How Long to Form Cultured Pearl?

Pearls are usually harvested after one year for Akoya pearl, 2–4 years for Tahitian and South Sea, and 2–7 years for Edison freshwater pearl.

Pearls grow at different rates, depending on the type of pears and a few other factors. Akoya pearl will grow up to 9mm in 10 to 14 months in diameter, a Tahitian pearl could grow 10mm in 18 to 24 months, while a South Sea pearl could reach 15mm in diameter in 2 to 3 years.

The longer you leave the clam to grow the pearl, the larger and of better quality, it will be.

cultured pearl necklace types
Different colors and shapes of freshwater pearls

If left for years to create a pearl, both freshwater and saltwater mussels can create pearls of great quality that will last you for years to come (even 50+ years). Quickly cultured pearls are lower quality because they have a too think coat of nacre, and they will wear out more quickly.

It’s interesting to note that not all pearls are created equal. Top jewelry makers create only 5-10% of pearls that are of excellent quality, but pearl farmers cultivate pearls of various quality and manage to sell them.

China is currently the world’s largest producer of freshwater pearls, producing more than 1,500 metric tons per year.

How Much Are Pearls Worth?

Typically, round freshwater pearl strands range from $50 to $2000, such as this beautiful pearl necklace. A strand of Akoya pearls cost from $300 to $10,000. Akoya pearls are the smallest types of cultured pearls on the market.

akoya pearl necklace and pearls

For cultured pearls, we can distinguish 6 quality factors:

  1. Nacre – the thicker and smoother, the more valuable
  2. Luster – the more reflection the pearl has the more valuable
  3. Surface – cleaner surface is more valuable
  4. Shape – round and even pearls are the most valuable
  5. Color – depends on the popularity and taste for the region

How much pearls are worth also depends on:

  • Wild vs Cultured pearl – Wild pearls are more prized
  • Freshwater vs Saltwater pearl – Saltwater pearls are a bit more valuable

Seed pearls are also one of the more expensive ones.

Seed pearls in human hand

Seed pearl is a small natural pearl, formed in either freshwater mussel or saltwater oyster, and it’s usually less than 2mm in diameter. Most of them today are created accidentally, and are very hard to prepare in a strand or jewelry piece.

Are Freshwater and Saltwater Pearls Worth the Same?

Generally speaking, they are not worth the same.

Saltwater pearls cost more than freshwater pearls, because they are many times more difficult to produce, and can only produce 1 or 2 pearls at a time. On the other claw, freshwater mussels grow up to 32 pearls per shell.

There you have it, all the important info about how long do pearls form.
This was fun to write.

Hopefully you learned something cool today. Check out my other cool posts!

  • Alex Mitch

    Hi, I'm the founder of! Having been in finance and tech for 10+ years, I was surprised at how hard it can be to find answers to common questions in finance, tech and business in general. Because of this, I decided to create this website to help others!