Mineral: Calcium Carbonate
Color: White, black, gray, yellow, orange, pink, lavender, green, blue
Refractive Index: 1.52-1.69
Specific Gravity: 2.60-2.85
Mohs Hardness: 2.5-3.0
Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of colors. The most familiar colors are white and cream (a light yellowish brown). Black, gray, and silver are also fairly common, but the palette of pearl colors extends to every hue. The main color, or bodycolor, is often modified by additional colors called overtones, which are typically pink (sometimes called rosé), green, purple, or blue. Some pearls also show the iridescent phenomenon known as orient.
Cultured pearls are popular for bead necklaces and bracelets, or mounted in solitaires, pairs, or clusters for use in earrings, rings, and pendants. Larger pearls with unusual shapes are popular with creative jewelry designers.
Personal Care Products can Damage Pearls
Cosmetics, sun block, perfume and hairspray all contain chemicals that can dramatically dull the luster of a pearl. The natural acids contained in body oils and perspiration can also damage pearls in the same way. It is best to put your pearls on at least 30 minutes after applying any personal care products, and to take your pearls off before getting ready for bed. A good rule of thumb to remember is that pearls should be the last things to put on and the first things to take off.
Simple Steps to Protect Your Pearls
Wiping the pearls with a damp, soft cloth after you wear them will ensure that they remain free of harmful build-up of compounds that may damage the nacre of your pearls. Always keep your pearls separated from hard jewelry items such as rings or bracelets to prevent them from being scratched. Pearls are best kept in a soft-cloth pouch or a soft-lined jewelry box. Never store your pearls in an airtight environment such a a zip lock bag. Pearls are organic and do contain trace amounts of water. Storing them in an airtight environment will cause them to become brittle and damage the luster.
When to Have Pearls Restrung
If you wear your pearls often, they should be strung about once a year to prevent strand breakage. We suggest the use of silk thread. However, nylon thread is an acceptable alternative. The thread should be knotted between each pearl to prevent all the pearls in a strand from falling off should a break occur. Knotting also prevents possible damage from the pearls rubbing against each other.
Both nylon and silk will soak up the oils from one’s skin and may turn dark after a time. Restringing the pearls with new silk or nylon is preferred over attempting to wash the thread, as cleaning may weaken or stretch the knots and some soaps may be abrasive and damage your pearls.
Lint-free cloths, such as this gem cloth, are ideal for removing oily film and dirt. Similar cloths are available at most hardware stores or through the GIA store.
DON’T USE HARMFUL SOLUTIONS
Chlorine bleach or abrasives (such as household cleansers or toothpaste) should never be used when cleaning diamond jewelry. Chemicals like chlorine can damage some of the metals used to alloy gold for diamond settings and abrasives can scratch gold and other metals.
USE ULTRASONIC CLEANERS WITH CAUTION
Sometimes an ultrasonic cleaner is necessary to remove encrusted dirt on diamonds. By sending low frequency sound waves through a solution, ultrasonic cleaners cause vibrating fluid to remove accumulated dirt and grime. But they can also shake loose stones from their mountings or chip the girdles of diamonds that are set next to each other. Proceed cautiously if the diamond contains feathers or is included, and avoid ultrasonics if the diamond has been treated by fracture filling.
Ultrasonic cleaners are used to remove heavy dirt and grime, but could cause damage depending on the stone, treatment or setting. It’s best to have your jeweler clean your jewelry using these machines to avoid any damage.
Before placing your diamond in an ultrasonic cleaner, it’s best to refer to the diamond’s grading report, which clearly discloses whether the diamond has been treated. You should also consult a professional jeweler who can determine if your jewelry needs repair, such as checking for loose stones and tightening them, before it is cleaned.
The key to a diamond’s sparkle lies in its facets – which work like a series of many tiny mirrors reflecting light in and out of the stone. Regularly cleaning the facets will keep your diamond sparkling and your diamond jewelry in gleaming condition, ready to shine for your next special occasion.
NATURAL PEARLS VS. CULTURED PEARLS
Natural pearls form in the bodies, or mantle tissue, of certain mollusks, usually around a microscopic irritant, and always without human help of any kind.
The growth of cultured pearls requires human intervention and care. Today, most of the mollusks used in the culturing process are raised specifically for that purpose, although some wild mollusks are still collected and used.
There are four major types of cultured whole pearls:
Akoya Cultured Pearls
Akoya cultured pearls are the most familiar type of saltwater cultured pearl to most people in the U.S and other western markets. Many customers think of white or cream colored akoyas as the classic pearl used for jewelry, especially single-strand necklaces. Japan and China both produce akoya cultured pearls.
South Sea Cultured Pearls
Australia, Indonesia, and the Philippines are leading sources of these saltwater cultured pearls. South Sea cultured pearls can be white to silver or golden, depending on the type of oyster. Their large size and thick nacre, due to a long growth period, plus their limited critical growing conditions are all factors contributing to their value.
Tahitian Cultured Pearls
Cultivated primarily around the islands of French Polynesia (the most familiar of these is Tahiti). These saltwater cultured pearls, sometimes referred to as black pearls, have a wide color range. They might be gray, black or brown, and they can have blue, green, purple or pink overtones.
Freshwater Cultured Pearls
Freshwater cultured pearls are the most commonly produced pearls and they are one of the most popular pearl types among shoppers and jewelry designers. This is due to their remarkable range of sizes, shapes and colors, plus their commercial availability at lower price points. They are usually cultured in freshwater lakes and ponds, often with many pearls grown in one oyster. China is the leading source for freshwater cultured pearls.