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Gemstones, Diamonds, and Pearls

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Before you start shopping for gemstones, diamonds, and pearls, it pays to do a little homework. Their cost and value can be affected by their size, by whether they’re natural or manufactured, and by whether they were treated to improve their appearance or enhance their value.

Shopping for Jewelry

When you start shopping for jewelry, you may be thinking about design, quality, and how much you want to spend. It helps to know where you can get the best jewelry for the best price.

As you search for a jewelry store or online seller:

  • Ask family members, friends, or coworkers for recommendations.
  • Find out what other people say about a seller by typing its name and the words “complaints” or “reviews” into a search engine.
  • Find the store’s refund and return policies — and get them in writing.

Also get to know the common phrases and markings used to describe the type of jewelry you’re looking for so it’s easier for you to decide whether a piece of jewelry is worth the price.

Gemstones

As you shop for gemstones, it helps to know that there are three main types of gemstone products:

  • Natural gemstones occur in nature. They can be rare and expensive.
  • Laboratory-created stones (also called synthetic, laboratory-grown, or manufacturer-created stones) have the same chemical, physical, and visual properties as natural gemstones, but they are manufactured. They are often less expensive than natural gemstones.
  • Imitation stones look like natural stones, but they are made of other less expensive materials like glass or plastic, and do not have the same chemical, physical, and visual properties as natural gemstones.

Laboratory-created and imitation stones should be clearly labeled. Imitation diamonds, like cubic zirconia, may look like diamonds but cost much less. Certain laboratory-created gemstones, like moissanite, may look just like natural diamonds, and the difference may not be adequately detected by the naked eye or even with a jeweler’s loupe. Ask the seller if they have testing equipment that can distinguish between natural diamonds and lab-created stones.

Size

You can measure a gemstone by weight, size, or both. The basic unit for weighing a gemstone is the carat — which is different from the “karat” used for gold. A carat is equal to one-fifth of a gram and is divided into 100 units, called points. For example, a half-carat gemstone weighs 50 points. When a gemstone is measured by its dimensions, the size often is expressed in millimeters; for example, 7x5 millimeters.

Treatments and enhancements

Some gemstones are treated to improve their appearance or durability, or to change their color. Some enhancements affect the value of a stone compared to a similar untreated stone. The effects of some treatments may lessen or change over time, and some treated stones might require special care, so you should ask if a gemstone has been treated.

Here are some common treatments and their effects:

  • Bleaching lightens and whitens some gemstones, including jade and pearls.
  • Diffusion treatment adds color to the surface of colorless gemstones. The center of the stone remains colorless.
  • Dyeing adds color and improves color uniformity in some gemstones and pearls.
  • Fracture filling hides cracks in gemstones through an injection of colorless plastic or glass to improve the stones’ appearance and durability.
  • Heating can lighten, darken, or change the color of some gemstones, or improve a stone’s clarity.
  • Impregnating some gemstones with colorless oils, wax, or resins hides a variety of imperfections to improve the stones’ clarity and appearance.
  • Irradiation can add color to colored diamonds, certain other gemstones, and pearls.

Diamonds

The four Cs of diamonds

A diamond’s value is based on four criteria.

1. Color often is graded on a scale established by the Gemological Institute of America (GIA). On the GIA scales, color is rated from D to Z, with D at the top. The more color a diamond has, the lower its value.

2. Cut refers to the quality of how the diamond has been shaped, taking into account the diamond’s proportions, polish, and symmetry.

3. Clarity measures the natural imperfections in the stone. On the GIA scales, clarity is rated from flawless to I3. A diamond can be described as “flawless” only if it has no visible surface or internal imperfections when viewed under 10-power magnification by a skilled diamond grader.

Some diamonds may be treated to improve their appearance. Some jewelers call the treatments “clarity enhancements.” The treatments include fracture filling and lasering, when a laser is used to remove black inclusions or spots from a diamond. A laser-drilled stone usually doesn’t require special care, but it may not be as valuable as an untreated stone. Jewelers should tell you if a stone was laser-treated.

4. Carat refers to the stone’s weight. The weight may be described in decimal or fractional parts of a carat.

  • If weight is described in decimal parts, the number should be accurate when rounded to the last decimal place. For example, “.30 carat” could represent a diamond that weighs between .295 and .304 carat.
  • If weight is described in fractions, a diamond described as ½ carat could weigh between .47 and .54 carat. If a seller gives a diamond’s weight in fractions, they should tell you the weight is not exact, and tell you the reasonable weight range for the diamond. For example, “The weight range for this diamond is .47 - .54 carats.”

Make sure your sales paperwork includes any information the seller told you when you made the purchase, like the gemstone’s weight or size, treatments, and special care requirements. Some jewelers may give you a grading report from a gemological laboratory.

Pearls

Pearls can be natural, cultured, or imitation.

  • Natural pearls are made by oysters and other mollusks.
  • Cultured pearls also are grown by mollusks, after people put irritants into the shells that cause pearls to grow.
  • Imitation pearls are manufactured with glass, plastic, or other materials.

Natural pearls are very rare, so most pearls used in jewelry are either cultured or imitation. . Cultured pearls usually are more expensive than imitation pearls. A cultured pearl’s value generally is based on its size, usually stated in millimeters, and the quality of its nacre coating, which gives it luster. Jewelers should tell you if pearls are cultured or imitation.

Jewelers should also tell you if pearls have been treated in a way that is not permanent, creates special care requirements, or significantly affects value. For example, some pearls occur naturally in black, bronze, gold, purple, blue, and orange tints. As with any other any other pearl treatments or enhancements, jewelers should tell you whether colored pearls were colored, dyed, or irradiated if the treatment is not permanent, creates special care requirements, or significantly affects value.

Report Problems

If you have a problem with a jewelry purchase, try to resolve it with the seller first. If you’re not satisfied, report it to:

The Jewelers Vigilance Committee (JVC) has a mediation program that helps some people who have disputes with jewelers. Read more at JVClegal.org/services.

If you have problems with jewelry bought from a company located outside the U.S., report it at econsumer.gov.

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