How are pearls created in nature?

Question

Which countries harvest natural pearls? , In which countries is the production of cultured pearls a major industry?

My kid needs this for a science extra credit thing and I find nothing of much use.....HELP!

Answer 1

A pearl is a hard, rounded object produced by certain animals, primarily mollusks such as oysters. Pearls can be used in jewellery and also crushed in cosmetics or paint. Pearl is valued as a gemstone and is cultivated or harvested for jewellery. The pearl is also the birthstone of the month of June.

Pearls are formed inside the shell of certain bivalve mollusks. As a response to an irritating parasite inside its shell, the mollusk will deposit layers of calcium carbonate (CaCO3) in the form of the minerals aragonite or calcite (both crystalline forms of calcium carbonate) held together by an organic horn-like compound called conchiolin. This combination of calcium carbonate and conchiolin is called nacre, or as most know it, mother-of-pearl. The idea that a grain of sand acts as a "seed" for the pearl is a myth.[1]

The unique lustre of pearls depends upon the reflection and refraction of light from the translucent layers and is finer in proportion as the layers become thinner and more numerous. The iridescence that some pearls display is caused by the overlapping of successive layers, which breaks up light falling on the surface. Pearls are usually white, sometimes with a creamy or pinkish tinge, but may be tinted with yellow, green, blue, brown, purple, or black. Black pearls, frequently referred to as Black Tahitian Pearls, are highly valued because of their rarity; the culturing process for them dictates a smaller volume output and can never be mass produced. This is due to bad health and/or non-survival of the process, rejection of the nucleus (the small object such as a tiny fish, grain of sand or crab that slips naturally inside an oyster's shell or inserted by a human), and their sensitivity to changing climatic and ocean conditions.

Pearls fit into two categories: freshwater and saltwater. As their name implies, freshwater pearls are formed in freshwater mussels that live in lakes, rivers, ponds and other bodies of fresh water. Most freshwater cultured pearls sold today come from China. By contrast, saltwater pearls grow in oysters that live in the ocean, usually in protected lagoons. Akoya, South Sea and Tahitian are the three main types of saltwater pearls.

Answer 2

This Site Might Help You.

RE:
How are pearls created in nature?
Which countries harvest natural pearls? , In which countries is the production of cultured pearls a major industry?

My kid needs this for a science extra credit thing and I find nothing of much use.....HELP!

Answer 3

I'm not sure which country's but this is how pearls are formed.
A piece of sand ends up inside the clam and to prevent the irritation the clam secretes a film of mucous around the grain of sand, the clam continues to due this and the film builds up and layer by layer these films harden up to form a pearl.
That pearl necklace or ring your wearing is clam mucous.

Answer 4

pearls come from oysters
a bit of sand get inside the oyster
and it cant pick at it for obvious reasons
so itll accumulate a saliva like substance
over time itll grow in size
and this saliva like substance becomes a pearl while removing the annoying sand

Answer 5

It happens when an oyster gets a grain of sand inside it. Then it coats the sand with a hard smooth substance in order to reduce the irritation. Over time the thing can grow to 6-9 mm in diameter.

Answer 6

oysters. how hard is it to find information on natural and cultured pearl formation?

Answer 7

pearls come from oysters ??? but to say as far as production wise, i think that would somewhere in the orient...remember pearl cream, the ancient chinese secret.

Answer 8

This site answers all your questions:
http://www.karipearls.com/how-are-pearls-made.html

Answer 9

spain make em,
made in oysters i think,
they are hardened mucus...
and black pearl is dearer i think?
http://www.pearl-guide.com/pearl-nucleus-manufacturing.shtml