GIA Articles

Diamond Buying Tips - GIA ArticlesPeople mark special events with sentimental gifts of jewellery. While weddings reign as the biggest diamond event, there are many small yet glorious celebrations that are honoured with beautiful sparkles, too, such as new jobs, anniversaries, graduations, births…the list, happily, is endless.


So how do people learn about diamonds so they can buy, own and enjoy them with confidence? The not-for-profit Gemological Institute of America (GIA), the world’s foremost authority in gems and jewellery and also the creator of the famous “Four Cs” of diamonds, offers these five tips:


Choose a qualified jeweller: Select a jeweller as you would a doctor, a lawyer or any professional. Ask around. Find someone who is a trained gemmologist, a GIA Graduate Gemologist or GIA Accredited Jewelry Professional, and is affiliated to a professional jewellery association.


Research: GIA’s Website offers in-depth information on diamonds, pearls and other gemstones. Knowing the Four Cs helps you speak the language of diamonds and communicate with jewellers.


Learn the "Four Cs": All diamonds are rare and no two diamonds are alike. A diamond’s quality and rarity is determined by its unique combination of characteristics of Colour, Cut, Clarity and Carat Weight. The International Diamond Grading SystemTM, used around the world since its invention by GIA in the 1950s, is based on the Four Cs.


- Carat: Diamonds are weighed in metric carats. Two carats weight about the same as a small paper clip. A carat is divided into 100 “points”, so a diamond of 50 points weighs 0.50 carats.
- Clarity: Nearly all diamonds contain unique clarity characteristics. Flawless diamonds are exceptional and costly. Most inclusions are invisible unless magnified.
- Colour: Colourless diamonds are quite uncommon. Most diamonds have a slight yellow or brown tint. GIA uses letters to represent colours, beginning with D (colourless) and ending at Z (light yellow or brown). “Fancy coloured diamonds” come in every colour imaginable, are also very unusual and have their own GIA Color Grading System.
- Cut: While diamonds come in different shapes, such as round, pear or marquise, the term "cut" refers to proportion. The well-cut, balanced diamond has unbridled brilliance, sparkle and fire.


Get an independent, diamond-grading report: A diamond grading report tells you the exact gemmological quality of your diamond. Is it a natural diamond? Is it a laboratory-grown diamond? Has it been treated and how? What are its quality ratings according to the Four Cs?


Have your diamond appraised and insured: A diamond grading report describes the precise gemmological quality of your diamond while an appraiser puts a monetary value to the stone. You can laser-inscribe a personal message or the diamond’s unique GIA Grading Report number on the diamond’s girdle.


Like true love, a diamond’s light and brilliance won’t fade with time.

Pearl Value Factors - GIA ArticlesIn the ever-changing world of hemlines and hairstyles, versatility is everything when it comes to keeping au courant with today’s fashion trends. Style makers from Jackie Kennedy Onasis to Madonna, however, have always seemed to agree on one thing: the appeal of pearls. Pearls have attracted and intrigued us for centuries. Sleek and modern with classical allure, today’s designers continue to show them with everything from couture to casual wear.


Today we can enjoy a wonderful range of both natural and cultured pearls. Natural pearl growth occurs when a mollusc protects or soothes itself from an irritation. The irritant may be a parasite or other tiny invader. The layers of protection form what is called “nacre,” and is what gives pearl its subtle beauty. Cultured pearls form in basically the same way, except that humans foster the irritation by placing a shell bead and/or a piece of mollusc tissue into the animal.


According to the Gemological Institute of America (GIA), an independent not-for-profit organization dedicated to protecting the interests of both the public and the jewellery industry, when shopping for cultured pearls, it’s important to look for a retailer who is recognized as a Graduate Gemologist (G.G.) or an Accredited Jewelry Professional (A.J.P.). In addition, GIA recommends consumers keep its “7 Pearl Value Factors” in mind:


Size: Pearl size is measured in millimeters. Typically, all other factors being equal, a larger pearl of a certain type is more expensive than a smaller one.
Shape: There are three main categories to pearl shape: spherical, symmetrical, and baroque. An example of a symmetrical pearl is an oval, while baroque pearls are irregular in shape
Colour: With cultured pearls, look at body colour and, if present, overtone. Body colour is the dominant colour of the pearl, while overtone refers to one or more translucent colours that overlie the body colour (like blush on a woman’s cheek). A third component of some pearls’ colour is orient. When present, it looks like a moving iridescence on or just below a pearl’s surface.
Lustre: This is the intensity of light reflected from a pearl’s surface. In general, more lustrous pearls will have a higher value. GIA uses the terms excellent, good, and fair to describe lustre on cultured pearls.
Surface Quality: This factor looks at the blemishes, or surface irregularities, on a pearl. Typical blemishes include bumps, abrasions, and spots; the visibility of the irregularities will affect the cost. Very few pearls, however, are completely free of blemishes.
Nacre Quality: Fine nacre quality means that a cultured pearl has a reasonable thickness of nacre around the nucleus as well as a high lustre.
Matching: This is the uniformity of appearance in strands and multi-pearl pieces of jewellery, and is judged by the consistency of all of the above factors.


Pearl Care

Cultured pearls do require a little special care to ensure a lifetime of enjoyment. Keep these four tips in mind:


  1. Apply any cosmetics, perfume and/or hairspray before putting on your pearls. If the pearls will be touching your skin, leave that area free of cosmetics or perfumes
  2. Don’t take pearls into the pool because the chlorine can affect their lustre.
  3. Clean your pearls periodically with warm water and mild, non-detergent soap. Never put pearls in an ultrasonic cleaner or use anything containing ammonia.
  4. Have your pearl strand re-strung every year or so by a jeweller.
Jewellery is one of our most intimate and cherished accessories. An elegant pair of pearl and platinum earrings, for example, makes an individual statement, nestled against the skin and resplendent in lustrous light. Yet, according to experts at the not-for-profit GIA, chemicals found in everyday substances like hairspray, lotions, perfumes, or other cosmetics can permanently damage the nacre of your dazzling pearl , and can corrode the alloys in that shiny setting. Understanding how to care for your treasured jewellery can make a world of difference in maintaining its beauty and keeping its heirloom quality sparkling for generations to come.


Jewellery Professional Cleaning - GIA ArticlesGIA says that light and heat can affect a coloured gemstone’s durability and colour. Just as the sun’s harmful rays can damage our skin, over time and in excess, it can also fade and weaken some gemstones, such as amethyst, kunzite, topaz, and pink conch-shell cameos. Pearls and other delicate materials, like ivory, will bleach under extreme exposure to light. Other gems, especially amber, can darken over time when exposed to too much light.


Excessive heat and sudden temperature changes may also fracture the gem. Heat can easily remove the natural moisture some gems need to keep their beauty. Pearls, for instance, can dry out, crack and discolour. Opals will turn white or brown, develop tiny cracks, and might lose their play-of-colour.


Exposure to chemicals can damage and discolour precious metals – gold, silver, and platinum – and may harm some coloured gems. Fine jewellery should be removed before diving into a chlorinated swimming pool, or before using household cleaners. Many of these cleaners contain ammonia, and are only safe for diamonds and the more durable coloured gems. Chlorine bleach, another common household solvent, can pit gold alloys.


GIA recommends cleaning most coloured gems with warm water, mild soap (no detergents), and a soft brush. A pulsed-water dental cleaning appliance and a soft, lint-free cloth can also be used. Be sure to stop the sink’s drain or use a rubber mat in case the stone comes loose from its setting.


Soft gems, such as pearls, on the other hand, can easily be scratched. GIA suggests using an unused makeup brush instead, and warm, soapy water. Lay the pearls on a towel to dry. The wet string can stretch—and attract dirt—so don’t touch a string of pearls until they are completely dry. Pearls worn every few days should be restrung once a year.


Proper jewellery storage is often overlooked. Jewellery should never be tossed into a drawer or on top of a dresser—that’s a recipe for scratches and fractured gems. Most jewellery pieces come in a box or pouch from the store, which is a perfect place to keep them. Sterling silver, for example, should be kept in an anti-tarnish bag or cloth.


Jewellery boxes that feature individually padded slots for rings, and posts for hanging necklaces and bracelets, are also ideal. Like pearls, opals draw moisture from the air. Storing your opal ring or pearl earrings in a dry area, such as a safety deposit box, can actually do more harm than good. When traveling with jewellery, protect the pieces from scratches or other impact damage by padding the jewellery.


Many jewellery stores offer free check-up or professional cleaning at scheduled intervals (once a year is common). GIA recommends consulting a professionally qualified jeweller, such as a Graduate Gemologist, Graduate Jeweler, or Accredited Jewelry Professional.