Pearls are the only gemstone that is created by an organic process within a living creature, and they don’t have to be cut or polished to be beautiful and useful in making jewelry! They are a soft gemstone ranging from 2.5 to 4.5 on the Mohs scale of hardness. Due to this softness, pearls should be protected from scratches and extreme wear.
Pearl Folklore, Legend, and Metaphysical Properties
Pearl is one of the birthstones for the month of June and for Gemini/Cancer. It has long been a symbol of purity and innocence which is why it is traditionally sewn into bridal gowns or worn as jewelry by a bride. The ancient Greeks believed that pearls were the hardened tears of joy from Aphrodite, the goddess of love and that wearing pearls would promote marital bliss and prevent newlywed women from crying. Other cultures believe that pearls bring the wearer love, money, protection, luck, wisdom through experience, quicken the laws of karma, cement engagements and love relationships, and to keep children safe.
According to some historians, humans collected pearls while searching for food because they believed that they provided the wearer with mythical powers such as good health, vitality, eternal youth and marital bliss. Many religious peoples adorned the walls of their temples and shrines with pearls. Some religions from the middle east believed that pearls were the “tears of God” that would fall from the sky and land in oysters soaking up the sun. These warm rays of sunlight and salty tears would then combine to grow a pearl when the oyster would return to the ocean floor.
Today we know that pearls are formed as a reaction to an irritant within a mollusk. Any mollusk, which is an invertebrate with a soft body protected by a shell, is capable of producing a pearl. However, only those mollusks whose shells are lined with the iridescent substance we call nacre, or mother-of-pearl, produce pearls that are used in jewelry.
Both cultured pearls and natural pearls are grown in mollusks. However, the cultured pearls are formed with human intervention. This means that the “irritant” is placed inside the mollusk by humans rather than from a spontaneous reaction to a random irritant.
Determining Pearl Quality
There are three main pearl types used in jewelry:
- South Sea (White, Golden and Tahitian)
Keshi pearls are a shape of pearl, not a type of pearl. They are created when a mollusk rejects the implanted nucleus and creates a pearl sacs entirely of nacre. They are generally small in size and their shapes vary broadly. They also come in a wide variety of colors and tend to have high luster and even orient. This is due to their solid-nacre composition. Most keshi pearls have a greater luster than even the best-quality cultured pearls. However, because they are a by-product of producing cultured pearls, they are not considered natural.
Pearls are measured by their diameter in millimeters. They can range from smaller than 1mm up to 20mm. If all other qualities are equal, the size will determine its value. Average size pearls today range from 6.5 mm to 11 mm.
Perfectly round pearls are actually quite rare. Most experts generally divide pearl shapes into three broad categories:
- Spherical Shapes – perfectly round or nearly round. They are the classic pearl shape
- Symmetrical shapes – balanced and regular. Would be mirror images if cut in half.
- Baroque shapes – irregular or abstract. These are non-symmetrical in nature and can be quite unique.
Within these three broad categories there are 8 sub-categories of shapes:
- Round – The “classic” shape. This is the most rare shape and are the most desirable. They obviously fall in the Spherical category.
- Near-round – Not exactly spherical. Could be slightly elongated or flattened but so close to round as to still be in the spherical category.
- Semi-round – Less round than near-round.
- Oval – Narrower at the ends than in the center. Still categorized as spherical.
- Button – These are flattened to some degree making them look like buttons or disks. They are often used to make earrings because the flattened shape makes them easier to attach to findings. Categorized as spherical as well.
- Drop – Drop shaped pears are shaped like tear-drops. Or pear shaped. They make attractive earrings or pendants due to their elongated shape. They are categorized as symmetrical.
- Baroque – These pearls are non-symmetrical and irregular in shape. Can be purely abstract in shape or could resemble something like a cross or stick. Categorized as baroque.
- Semi-Baroque – These are only slightly irregular in shape. For example, a pearl that could be considered one of the other shapes but not symmetrical is a Semi-baroque and would fall in the baroque category.
There are three main color characteristics:
- Body-color – the dominant overall color of the pearl. For example some naturally occurring colors include white, champagne, aqua, green, golden and black
- Overtone – the translucent color that appears over the body-color. These could include a white pearl with rose overtones, or a black pearl with iridescent overtones.
- Orient-iridescent – these are the rainbow colors shimmering on or just below a pearl’s surface. A true rainbow iridescent color is extremely rare.
Luster is the most important factor when considering the beauty of a pearl. It’s more than a combination of surface brilliance and glow. It is caused by light travelling through the translucent layers of nacre and reflecting back to they eye from within the pearl. The highest quality pearls will have a sharp, mirror-like luster that shows a high level of reflection.
There are 4 categories of luster:
- Excellent – reflections are bright, sharp and distinct.
- Good – reflections are bright but not sharp and they are slightly hazy around the edges.
- Fair – reflections are weak, hazy and/or blurred.
- Poor – reflections are dim and diffused.
Pearl Surface Quality
Because pearls are organic, there can be a great variation in their surface quality. The cleaner the surface is, the more valuable the pearl is.
There are 4 categories of surface quality:
- Clean – blemish free or such minute surface distortions as to be very difficult to see.
- Lightly Blemished – minor irregularities.
- Moderately Blemished – Noticeable surface distortions and characteristics.
- Heavily Blemished – Obvious surface irregularities.
Pearl Nacre Quality
Nacre quality is just as important as the surface and luster qualities and can be classified in three ways:
- Acceptable – nucleus is not noticeable and no chalky appearance.
- Nucleus Visible – the bead nucleus shows through the nacre.
- Chalky Appearance – there is a dull, chalkiness to the surface of the pearl.
Because pearls are an organic and porous gemstone, it is important to keep them free of our everyday cosmetics. Therefore, it is recommend that pearls be put on after hair has been sprayed and make up applied. If it becomes necessary to clean them, do NOT use jewelry cleaners! Simply wipe them with a damp cloth. The best way to take care of your pearls is to wear them! The oils from your skin help to keep them from drying out. And when you store them, put them in a soft pouch to keep them from getting scratched.
The most important thing to remember when looking for the right pearls for your new piece of jewelry, is to look for the shape, color, and luster that speaks to you. Then and only then will you be happy with your choice!
Pearl Knowledge. (n.d.). . Retrieved June 2, 2014, from https://www.rawpearls.com.au/pearl_knowledge/how_cultured_pearls_are_grown
Pearl Facts, Information and Description. (n.d.). Pearl. Retrieved June 2, 2014, from http://www.bernardine.com/gemstones/pearl.htm
Powley, T. (n.d.). The Power of Pearls – All About Pearls and Pearl Jewelry. About.com Jewelry Making. Retrieved June 2, 2014, from http://jewelrymaking.about.com/od/pearljewelryinfo/a/about-pear
Originally published in June, 2014 on the blog for Jewelry By Morgan.