Diamond Jewelry Buying Guide

Diamonds are the hardest naturally-occurring substance on Earth, but they still can chip. When you shop for diamond jewelry, choose your setting wisely. Four-prong, six-prong, and low-profile channel or bezel settings are more apt to protect your diamonds. When you get your diamond jewelry home, store pieces individually in soft cloth pouches to prevent jewels from bumping against one another.

Know Diamond Cuts and Shapes

Diamond shapes range from traditional round cuts to hearts, pears, and more. Your choice should reflect the tastes of the person who will be wearing the jewel.

A well-cut diamond reflects light to maximize the stone's brilliance. Cut has three components: 

Diamond cut grade: A standard grading report describes cut by the shape or outline of the diamond and the pattern of the facet arrangement (also known as cutting style).

Diamond cut depth: Diamonds cut too shallow or too deep lose light through the bottom or sides, causing the stones to sparkle less.

Diamond polish: A poor polish, or rough facets, can diminish a diamond's brilliance, as well as its value.

Determine Diamond Carat Weight

Diamond size is measured by weight in carats or points. Because larger diamonds are rare, prices rise considerably as carat weights increase. If your primary shopping concern is high carat weight, a moderate downgrade in carat size (e.g. 0.05) can save you a lot of money and still look beautiful.

Study Diamond Clarity

Most diamonds contain inclusions (tiny mineral traces or flaws) often invisible to the naked eye. A diamond's clarity is determined by the amount and severity of these inclusions. Flawless diamonds are very rare and more expensive. eBay sellers often describe the clarity of larger, solitaire diamonds by referring to the industry letter grading scale. For example, the International Gemological Institute (IGI) uses the following grading scale for clarity:

Consider Diamond Color

Most diamonds appear white to the naked eye, but they all include trace amounts of yellow color, with the most valuable diamonds falling in the colorless range. However, a deeply colored diamond such as a brilliant canary yellow diamond can cost more than its colorless counterpart.

Fancy diamonds, also called Z+ diamonds, come in a variety of colors including deep yellow, pink, green, orange, blue, red, and black.

Spot Certified Diamonds

Many sellers include diamond appraisal (estimated retail value) and certification information in listings. Certificates, official documents issued by third-party gemological labs, include specifics about an individual gem (at least the four Cs) independent of market value. It can include information about diamond quality, validation that a diamond is organic, and the serial number on the girdle of laser-inscribed diamonds.

To buy a quality diamond:   

Look for reputable gemological labs: Make sure a reputable gemologist or gemological lab issued the grading certificate. You'll have trouble determining impartiality and stringency of no-name laboratories.

Evaluate the grading certificate's photo: Look for listings with a picture of the grading certificate and its serial number. Some labs offer online services where you can type in the serial number and verify that the lab graded the diamond and that the specifications are the same.

Discover the origin of a diamond: Ask sellers for more information about their process for confirming the origin of their diamonds so you don't end up buying a conflict diamond. Some eBay sellers specify their diamond "Kimberly Process confirmed." The Kimberly Process, formally launched in January 2003, attempts to certify international diamonds and identify the origins of each diamond.

Research gemological labs

Acquaint yourself with gemological labs before purchasing your diamond. Lab reputations may very and change over time. Popular labs that certify diamonds and gemstones include:

Gemological Institute of America (GIA): Many in the industry consider GIA the gold standard of diamond graders. Established in 1931, the not-for-profit GIA has its headquarters in Carlsbad, California and has a presence in a number of locations worldwide.

International Gemological Institute (IGI): IGI grades diamonds and gemstones from its headquarters in New York and several other U.S. locations.

American Gem Society Laboratories (AGSL): Founded in 1978, the AGSL is based in Las Vegas, Nevada.  

European Gemological Laboratory USA (EGL-US): There are a few independently owned grading labs that carry the EGL name. EGL-US certificates, however, are the only EGL certificates permitted in the United States. EGL-US has been independently owned since 1986, and is based in New York.

Select Other Diamonds & Crystals

Not all diamonds come straight out of nature. Common enhancements include:
Clarity-enhanced diamonds: Clarity-enhanced diamonds have undergone treatment to remove visible imperfections. In the clarity enhancement process microscopic amounts of material similar to a diamond are inserted into the flaws. Light then flows freely through the diamond eliminating the imperfection from view. Because the material is used in small quantities, it does not add to the weight of the diamond.

Color-enhanced diamonds: Color-enhanced diamonds have undergone treatment to alter or heighten color. A number of procedures can change a diamond's natural color, including irradiation using high-energy particles. Depending on resulting color, “after” colored diamonds can be more expensive than their untreated counterparts. The safe irradiation process does not affect any aspect of the diamond other than color.  

Laser-drilled diamonds: Laser-drilled diamonds have undergone treatment to remove inclusions with a laser. Laser drilling provides permanent inclusion removal and does not affect the diamond's strength.

High Pressure High Temperature (HPHT) diamonds: HPHT diamonds are created by simulating geological conditions that produce organic diamonds. A small nucleus providing the core of the diamond is placed on a surface of carbon. Then extreme pressures and temperatures are applied. The carbon then forms into a diamond crystal.

Chemical Vapor Deposition (CVD) diamonds: The CVD process mixes carbon in its gas form with hydrogen and methane gas. When heated, the mixture pours onto diamond kernels that slowly grow into diamonds.

Diamond look-alikes are also readily available:

Cubic Zirconia: Cubic Zirconia, abbreviated CZ, is made from Zirconium Oxide. CZ bears a strong resemblance to diamonds, but does not contain the same impurities. Professionals (and some laymen) can tell the difference between diamonds and CZ by looking at a stone’s facets and clarity under magnification.

Moissanite: Moissanite, a diamond look-alike created from silicon carbide, has properties similar to diamonds including extreme hardness, brilliance, and inclusions. Because of these close similarities Moissanite often costs more than CZ.   

Simulated diamonds:  Simulated diamonds are crystals cut to resemble diamonds. They do not have the strength or sparkle of natural diamonds.

Buy Diamonds with Confidence

Before making your purchase, make sure you know exactly what you're buying, research your seller, and understand how eBay and PayPal protect you.

Know what you are purchasing:

Carefully read the details in item listings.

Figure delivery costs into your final price. If you spend a lot of money, make sure the seller will insure the item when it ships.

If you want more information, ask by clicking the "Ask seller a question" link under the seller's profile.

Always make sure to complete your transaction on eBay (with a bid, Buy It Now, or Best Offer). Transactions conducted outside of eBay are not covered by eBay protection programs.

Never pay for your eBay item using instant cash wire transfer services through Western Union or MoneyGram. These payment methods are unsafe when paying someone you do not know.

Know your seller

Research your seller so you feel positive and secure about every transaction.

What is the seller's Feedback rating? How many transactions have they completed? What percentage of positive responses do they have?

What do buyers say in their Feedback? Did the seller receive praise?

Most top eBay sellers operate like retail stores and have return policies. Do they offer a money-back guarantee? What are the terms and conditions?

Buyer protection

In the unlikely event that a problem arises during your transaction, eBay and PayPal are there for you.

Pay safely with PayPal: PayPal (http://pages.ebay.com/paypal/buyer/) enables you to pay without the seller ever seeing your bank account or credit card numbers. In fact, PayPal protects buyers 100% against unauthorized payments from their accounts. Plus, with PayPal Buyer Protection, your purchase can be covered up to $1,000.

eBay Security & Resolution Center: Visit the Security & Resolution Center (http://pages.ebay.com/securitycenter/) to learn how to protect your account and use eBay's quick and efficient resolution tools.