Hawaii Pinctada margaritifera. Ho Tay Cristaria plicata. Vietnam Pinctada fucata. Pearls can be found in the most unlikely places. Australia Where are pearls found? Enjoy this page? Please pay it forward. Here's how Would you prefer to share this page with others by linking to it? Click on the HTML link code below. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.
Cristaria plicata River shell, wrinkle shell , Hyriopsis cumingi Triangle shell. Nacre is formed from iridescent layers or columns of flattened crystallised calcium carbonate, in the form of the mineral aragonite ah-RAG-uh-nite , secretions over the irritant. These microscopic aragonite crystal layers, called platelets, are held together by conchyolin kon-KY-uh-lin , an organic binding agent.
Pearl oysters are members of the phylum Mollusca and belong to the class Bivalvia. Most pearl producing mollusks are bivalves, meaning their shells have two halves connected by a hinge like a clam , a soft body with a small foot, a byssal gland and paired gills. Most bivalves are also passive filter feeders - meaning they maintain an open relationship with the environment by constantly circulating water through their shell in order to support their food supply.
The anatomy of a bivalve mollusk facilitates the production of pearls. The mollusk opens its shell slightly to allow water to enter its body as it extracts microscopic food particles from the water.
The open relationship of the bivalve structure increases the probability of the entrance of foreign objects and creatures. This is critical for pearl production since most natural pearls are formed as a reaction to a parasite or foreign object within the shell. A pearl-producing mollusk can live in freshwater or saltwater. Freshwater mollusks are referred to as mussels while saltwater mollusks are referred to as oysters. While the name "pearl oyster" suggests a close relationship with other types of oysters, pearl oysters are actually a distinct species from edible oysters and have important anatomical and behavioural differences.
There are a small number of mollusks capable of producing a pearl and only those mollusks that have shells lined with nacre NAY-kur , the pearlescent substance inside the animal's shell produce the pearls used in the jewellery industry. Pearl oysters feed on small algae found in the water column. The gills in bivalves are large and tiny hair-like cilia on the gills are used to remove small particles from the water.
Both adults and larvae feed on algae and other small organisms. Clear tropical waters contain limited amounts of algae. Therefore, a large amount of water must be filtered daily in order for the pearl oyster to obtain sufficient food. This is the reason importance is placed on not crowding pearl oysters on the farm and for keeping the shells clean from organisms that compete for food.
Pearl oysters are protandric hemaphrodites which means that most are first male, then female. The male phase usually occurs during the first 2 to 3 years of life, with the change to the female phase in later years. Pearl oysters have been reported to live as long as 25 years. Pearl oysters reproduce by releasing millions of eggs or sperm into the water column where fertilisation occurs randomly.
In less than 24 hours, the fertilised egg develops into a trocophore larva, a free-swimming organism. The larvae remain suspended in the water column for 2 to 3 weeks before undergoing metamorphosis, changing into an attached juvenile "spat". Shortly before metamorphosis, the larva develops an enlarged foot and an eye-spot. The foot remains after metamorphosis and the young spat retains the ability to move about for several months even after it attaches itself to a hard substrate.
Pearl oysters can attach and reattach themselves using the byssus. Sometimes a natural pearl forms when an irritant, such as a fragment of shell becomes lodged inside the mollusk when it is feeding, or a parasite drills through the shell. To protect itself, the mollusk forms a sac around any irritant or invader that managers to get caught up inside its body.
This sac secretes nacre to cover the irritant and, over time, the growing pearls are completely covered with the beautiful iridescent substance we call nacre, or mother-of-pearl. The nacre and sac materials are made by the mollusk's mantle, the layer of tissue cells that surround the body of the mollusk and lines the shell.
The mantle tissue cells that make up the pearl sac are called epithelial ep-uh-THEE-lee-yuhl cells. One commonality all cultured pearls share is the nucleus. Sandy areas prove the most successful. You can find mussels in rivers, lakes, and streams. You can also choose to wade into the middle of shallow waters to find pearl mussels.
All you have to do is feel around the bottom until you find some mussels to bring to the surface. In lakes, you will likely need some basic diving equipment in order to find mussels with pearls. Generally speaking, saltwater pearls will require you to do some diving. The only thing to bear in mind is that mussels can be difficult to find as they blend in with the natural silt and sand of the river. Pearls form inside of oysters under rather extraordinary circumstances. Largely, a natural pearl will start to develop within the inside of an oyster shell when an invasive outsider, something as tiny as a grain of sand, actually slides in between the two shells of the oyster..
To do this, the oyster will rapidly strive to cover the uninvited intruder with visible layers of nacre. Layer upon layer of this nacre known as the mother of pearl is used to coat the intruder until a small iridescent gem is formed.
As mentioned above, there are some differences between natural and cultured pearls. It is important to keep this in mind as you seek to find oysters with pearls because this can dictate how and when you strive to find your pearls.
However you want to find oysters with pearls is fine, but it is important to note the differences between cultured and natural pearls. To start, color does not really come into play when it comes to natural or cultured pearls.
Both can come in a rainbow of hues. While many of us think of pearls as being ivory white like teeth, they actually come in a myriad of distinctive colors. The most common colors for both natural and cultured pearls are gray, red, blue, green, and even black. Natural pearls are simply pearls that form naturally within an oyster or mussel. As mentioned above, these pearls form when invaders like sand or food particles get into the mollusk. To protect itself, the oyster or mussel will cover the invader with the mother of pearl, which results in a natural and beautiful pearl.
Cultured pearls are those that are crafted with some major help from human-kind. Rather than letting nature take its course, pearl harvesters and farmers will cut small slits in the mantle of the oyster and insert invader irritants in an attempt to get the oyster to create pearls. The major difference is that cultured pearls are more affordable. Since they can be harvested regularly, they are not rare, nor is there a very taxing process involved with securing the pearls.
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