The Beauty of the Pearl

by

Jeff McPherson

http://www.emporia.edu/earthsci/amber/go340/students/mcpherson

Image taken from
http://www.brooksfinejewelry.com/info/gemstone_descriptions/


This webpage project was created for a gemstones and gemology course in the spring of 2004 semester at Emporia State University. The assignment was to learn webpage creation, as well as present a summary of some of the knowledge that I have acquired during the semester. I hope that you find it interesting as well as informative.


Table of Contents

Image taken from
http://www.romantique-jewelers.com/pearls.htm

Introduction

Pearl Formation

Properties of Pearls
Basic Properties
Value Properties

Types of Pearls
Natural
Cultured
Imitation

Caring for Pearls

References

Related Links


Introduction

This website was prepared to share some information on what I find to be one of the most interesting gemstones in the world, the pearl. Pearls are a very unique gemstone because unlike other gems that may have been created deep below the earth's surface through a process of heat and pressure, pearls are created under the water's surface inside a living creature. The first pearl was probably discovered many thousands of years ago along some remote beach somewhere while someone was searching for their dinner. It is this curious creation that has many people fascinated with the pearl.

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Pearl Formation

Pearls are formed when a foreign object such as a piece of sand, or even a small parasitic creature gets trapped in the shell of a mollusk. As a way of protecting itself from the debris the mollusk secretes a solution called the nacre. This is the same material that makes up the mollusk's shell. This secretion coats the sand or debris with many layers of material. Eventually the debris is covered completely with the nacre and a pearl is formed. Depending on the size of the finished pearl this process can last many years.(http://www.krystallinegems.com/pearls.htm)

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Properties of Pearls

There are two different categories when it comes to the properties of a pearl. The first category is basic properties which are used more for identification purposes. The second category is made up of the properties that contribute to the value of the pearl.

Basic Properties:

  • Color: white, pink, silver, cream, golden-colored, green, blue, and black
  • Color of Streak: white
  • Moh's Hardness: 2.5-4.5
  • Density: 2.60-2.85
  • Cleavage: None
  • Fracture: Uneven
  • Crystal System: Orthorhombic
  • Chemical Composition: Calcium carbonate, organic substance, and water
  • Transparency: Translucent to opaque

  • (Schumann, 1997)

    Value Properties:

  • Size: The larger the pearl the more valuable it is considered because
    of the time it took for the mollusk to create it.
  • Shape: This is the degree of symmetry and roundness that the pearl
    shows. The more round the pearl is the higher value it carries. The
    pearl is rated on a scale which is made up of, round, drop, button,
    oval, semi-round, circle or ringed, to the oddly shaped which are
    referred to as baroque.
  • Nacre Thickness: This is the thickness of the surface layer, mother
    of pearl, that the mollusk has applied to the foreign object that
    is within the shell. This thickness is directly related to the
    durability and beauty of the pearl. If the layer is too thin then the
    pearl can easily be scratched. You may also be able to see through the
    surface coating, which would hurt the beauty. The thicker the nacre
    the more valuable the pearl.
  • Luster: Luster is the reflectivity or glow of the pearl. The luster
    is ranked from high to low. The most valuable pearls will have a
    highly metallic luster.
  • Color: In this category the pearl is rated based on what is referred
    to as the base color, and the overtone, which is the colors that may be
    laying over the base color. This category is more personal preference
    but the value is based on the demand of a certain color at a given
    time.
  • Texture (surface blemishes): This refers to any imperfections that may
    be found on the surface of the pearl. The pearls value depends on the
    number, the size, and the visibility of the imperfections.
  • Matching: In order to make an attractive pearl necklace or a pair of
    pearl ear rings it is important that the pearls used are uniform. They
    have the same color, shape, size, and luster. If a necklace or pair of
    ear rings possess this uniformity they will be more valuable than one
    that does not.

  • (http://www.jewelry-appraisal.com/330_Perls.htm)

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    Types of Pearls

    There are three basic types of pearls, natural, cultured, and imitation.

  • Natural: pearls occur in nature with no intervention from man.
    They can occur in the ocean as well as in freshwater. Some of the most
    common places in which natural pearls can be found include, the
    Persian Gulf, New Guinea, Borneo, the Gulf of California, the Gulf of
    Mannar, North Western Sri Lanka, off the north coast of Australia,
    Tahiti, the Mergui Archipelago, the Sulu Sea, Venezuela, and Mexican.
    Even though they can be found in all these places around the world they
    are still the most rare type of pearl.
  • (Schumann)
  • Cultured: pearls form in basically the same way the natural
    pearls are formed except for one big difference. Instead of the
    foreign object entering the mollusk's shell on its own it is carefully
    implanted by humans without damaging the mollusk. The most
    common "seed" that is added is a small piece of shell. These can also
    take place in freshwater or saltwater. Cultured pearls can take an
    average of about 3.5 years to fully form, some take longer some take
    less time depending on the location and the water they are formed in.
    There are many different types of cultured pearls, among them are,
    South sea pearls, which can be found in both the white varieties as well
    as the black varieties, often referred to a Tahitian pearls. There are
    Akoya pearls which come in both Chinese varieties as well as Japanese
    varieties, to name a few.(http://www.pearls.com/visitors/visitors%
    20how_pearls_are_formed_and_their_1.htm)
  • Imitation: pearls are commonly made up of a combination of
    glass, wax and fish scales. Although these can be a very cheap
    alternative to a real pearl, they will not last nearly as long and there is no
    comparison when it comes to the luster and the beauty of the real thing.
    (Schumann)

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    Caring for pearls

    Because pearls have a hardness of 2.5-4.5 it is very important that great care is taken not to use anything abrasive when cleaning them. It is important to keep in mind that substances you may come in contact with everyday may affect your pearls. Pearls can be harmed by cosmetics, hair spray, perfume, powdered cleaners, bleach, and even perspiration. For general maintenance wipe your pearls with a soft towel after every wearing. To clean pearls use warm water and a mild soap, like a dish soap. Lay the pearls on a soft dry towel to allow them to dry. If it is a necklace you are cleaning it is important that you do not hang your pearls or wear them before the string is dry. If you do you could stretch the string. To store your pearls it is a good idea not to put them with other jewelry as they could get scratched very easily. A soft cloth bag is ideal for storage, this will protect them from dust and anything else that could scratch them.(http://www.fmnh.org/pearls/fun11.html)

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    References

    Image taken from
    http://www.broomecam.com/gold/moonlightpearlextra.htm

    Brooks Fine Jewelery, Gemstone descriptions, World Wide Web homepage URL: http://www.brooksfinejewelry.com/info/gemstone_descriptions/ accessed 4-18-04.

    Romantique Jewelers, Pearls, World Wide Web homepage URL:
    http://www.romantique-jewelers.com/pearls.htm accessed 4-18-04.

    Deep Sea Moonlight Pearls, World Wide Web homepage URL: http://www.broomecam.com/gold/moonlightpearlextra.htm
    accessed 4-21-04.

    Pearl Care, World Wide Web homepage URL: http://www.fmnh.org/pearls/fun11.html accessed 4-17-04.

    Understanding Pearls, World Wide Web homepage URL: http://www.jewelry-appraisal.com/330_Perls.htm accessed 4-17-04.

    Pearl Types, World Wide Web homepage URL: http://www.krystallinegems.com/pearls.htm accessed 4-17-04.

    How Pearls are Formed and Their Various Types, World Wide Web homepage URL: http://www.pearls.com/visitors/visitors%20how_pearls_are_formed_and_their_1.htm accessed 4-17-04.

    Schumann, Walter. 1997. Gemstones of the world. Sterling Publishing Co., Inc.
    New York.

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    Related Links

    Gemstones Syllabus

    Webpage Assignment

    Past Student Webpages

    Gemstone Links

    For more information email jeffbmcpherson@hotmail.com. This page was put online April 27, 2004.