Ernie and Regina Goldberger of the Josam Diamond Trading Corporation. This book could never have been written without the experience and knowledge I gained from working with them. A large percentage of the loose diamonds pictured in this book are or were part of their collection.

Mineralogist John S. White. He has edited this book as well as most of my other books. Thanks to his recommendations and corrections, my books are mineralogically and technically more accurate and thorough.

Eve Alfillé, Chuck Atmore, Daniel Ballard, Charles Carmona, Christopher J. Cart, Judith Conway, Michael Cowing, Branko Deljanin, Gary Dulac, Patricia Esparza, Elaine Ferrari-Santhon, Michael Francis, Al Gilbertson, Sean Hagens, Garry Holloway, Laurie A. Hudson, Catherine & Michael Jensen, Susan B. Johnson, Douglas Kato, Rahul Karnavat, Krista Kuether, Joe Landau, Arthur Langerman, Jurgen Maerz, Peter Malnekoff, Mark B.Mann, Garbis Mazmanian, Gary Megal, Marian Newton, Carlos Pulido, Barry Rogoff, Howard Rubin, Cassie Saget, Debra Sawatsky, Sindi Schloss, Kathrin Schoenke, Dr. James E. Shigley, Peter Solomon, Dale Swanson, Tom Tashey, Thom Underwood, Eric Walls and Sharrie Woodring. They have made valuable suggestions, corrections and comments regarding the portions they examined of this edition and/or a previous edition of the Diamond Ring Buying Guide. They are not responsible for any possible errors, nor do they necessarily endorse the material con-tained in this book.

The teachers at GIA. They helped me obtain the technical background needed to write a book such as this. Their dedication and assistance extend well beyond class hours.

Ebert & Company, Patricia Esparza, Douglas Kato, J. Landau, Inc., Lisa Poff Cox, Rainbow G. J. Diamonds, Ralph Shapiro, Marge Vaughn and the Yehuda Diamond Co. Their stones or jewelry have been used for some of the photographs.

Abe Mor Diamond Cutters, Eve Alfillé, Alishan, Alrosa,, Ambar Diamonds, American Gem Society, Amgad Natural Color Diamonds, Asian Institute of Gemologica Sciences, John Atencio, Baroka Creations, James Binnion, Michael Bondanza, Christopher Designs, Michael Cowing, Dali Diamond Co, Dejan Studio Design, Diamco, Exroyal Co., EGL USA, Finesse Diamonds, Gemological Institute of America, GCAL, Gemstone Designs, John Giovanni Goldsmiths, William Goldberg, Alan Hodgkinson, Michael & Catherine Jensen, Hubert, Kirk Kara, K.R. Diamonds, J. Landau Inc., Lang Antique & Estate Jewelry, Arthur Langerman, Lashbrook Designs, Leibish & Co, Lieberfarb Inc., Lili Diamonds, Lotus Colors Inc, Luc Vets Diamonds, Mémoire, National Diamond Syndicate, Avi Paz Group, Platinum Guild International USA, Toby Pomeroy, Raiman Rocks, RCDC Corp, Todd Reed, Reflective Jewelry Rio Tinto, Barry Rogaff, Royal Asscher Diamond Company, Sarosi by Timeless Gems, George Sawyer, Mark Schneider, Ernest Slotar, Brenda Smith, Sotheby’s Hong Kong, State Parks of Arkansas, Stuller, Suberi Bros., Tycoon Jewelry, Varna Platinum, Steve Vincent Design, Michael Werdiger, Inc., Sharrie Woodring, Yehuda Diamond Co. and Zaffiro. Photos and/or diagrams from them have been reproduced in this book.

Louise Harris Berlin. She has spent hours carefully editing the Diamond Ring Buying Guide. Thanks to her, this book is much easier for consumers to read and understand.

My sincere thanks to all of these contributors for their kindness and help.

The 4 Cs system was developed by GIA (Gemological Institute of America) in the 1950s. At that time, cloudy diamonds were considered industrial grade stones and were not set in jewelry, so transparency was not an issue. Neither was the treatment status because almost all diamonds were untreated. There were no separate price lists for rounds and other shapes. Therefore, it didn’t matter that “cut” referred to both shape and the quality of the cut. The only lab-grown diamonds that were available were tiny stones that were used as industrial abrasives.

The diamond industry has evolved and times have changed. High quality lab- grown diamonds have become widely available and sell for much less than natural diamonds. However, manmade diamonds are not always disclosed as such.

Cloudy and hazy diamonds are often used in jewelry today, but their clarity grade on lab reports does not necessarily reflect their lower transparency and value.

More and more diamonds are being treated to improve their color and apparent clarity grades; the price difference between treated and untreated diamonds can be significant so you should ask if the diamonds you’re considering buying are treated. Even though treatments are supposed to be disclosed, not all sellers disclose them.

Cutting style and shape are distinct price factors from cut quality and many gem labs now issue diamond reports with cut grades.

In short, if you want to make accurate diamond price comparisons and get good buys, consider 6 Cs and 2 Ts instead of only 4 Cs.

Cut quality assessment involves two fundamental considerations:

These are separate factors. A diamond can have high brilliance yet have bulky proportions that make it look small for its weight face up. Chapter 6 explains how to use the profile view of a diamond along with proportion measurements to help you determine if a diamond has unnecessary weight that makes it look small for its weight and it shows with photo examples some basic ways to judge brilliance from the face-up view.

Evaluate diamond brilliance both with the naked eye and magnification using a diffused light source such as a fluorescent lamp with a translucent white cover. Cut quality is a crucial factor which can affect prices by as much as 50%.

Each letter on the grading scale represents a narrow color range, not a specific point. A diamond is not poor quality just because it’s yellowish. It’s simply worth less because there’s a higher demand and lower supply of natural colorless diamonds.

Diamonds with a natural body color other than light yellow, light brown or light gray are called fancy color diamonds. These colored diamonds may cost a lot more than those that are colorless. For example, a one-carat natural pink diamond could sell for five to fifteen times more than a D color diamond of the same size and quality.

Some diamonds are colored artificially by irradiation or high-pressure high-temperature treatments. They’re worth significantly less than natural-color diamonds. In the GIA system, treated colored diamonds are not considered fancy diamonds. But in the trade, they’re sometimes referred to as “treated (enhanced or processed) fancy diamonds.” Chapter 5 has more details on color grading and fancy-color diamonds.

There is a difference between the labels 1 ct TW (one carat total weight) and 1 ct (the weight of one stone). A ring with a 1 ct top quality diamond can be worth more than 10 times as much as a ring with 1 ct TW of diamonds of the same quality.

When you price diamonds, think in terms of the per-carat cost. To calculate the per-carat cost of a diamond, use the equation: stone cost ÷ carat weight = per- carat cost of a stone. See Chapter 3 for additional information on carat weight.

Brilliant-cut square diamonds (princess cuts) may cost slightly more than step-cut squares, depending on size. They have the same shape but different faceting styles.

Patented and trademarked cutting styles typically sell for more than generic cuts of the same shape.

The most dramatic impact of stone shape and cutting style on price is with fancy color diamonds because their face-up color can be intensified by the shape and faceting style, and because the rough is so expensive. The price difference between some shapes can range from 10% to 100% depending on the diamonds and the dealer selling the stone. Chapter 4 shows and describes different cutting styles and shapes.

Clarity grading is further discussed in Chapter 7.

Mineralogists use the term diaphaneity but gemologists prefer the term “transparency” because it’s easier for lay people to understand.

Not all diamonds are transparent. Some are cloudy or translucent because they have fine particles not individually visible at 10x magnification which interrupt the passage of light. Normally, the higher the transparency the more valuable the diamond.

Even though transparency can have a significant impact on price, lab documents do not include it as a price factor. Gem labs, however, may take it into consideration when assigning a clarity grde. In addition, the comments section of lab reports may state “the clarity grade is based on clouds that are not shown.” Some labs identify translucent diamonds as “fancy white diamonds” and may omit a clarity grade.

If you’re interested in buying a brilliant diamond, choose one with high transparency. You don’t need a lab report to help you do this. Your eye is the best judge of transparency. Make sure the diamonds you’re comparing are clean and be aware that transparency is an important price and beauty factor. For more information on evaluating transparency, see Chapter 7.

If you are buying an untreated diamond, have it identified as untreated on the receipt. Fracture filling, laser drilling and coatings can be detected by jewelers and appraisers. Accurate detection of irradiation and HPHT treatment normally requires the special expertise and sophisticated equipment of a qualified independent gem laboratory. An important reason for buying a diamond accompanied by a lab report is to verify whether or not the color and clarity are natural. Diamonds colored by irradiation or HPHT treatment are a fraction of the cost of natural fancy color diamonds. For example, a one-carat irradiated “fancy” green diamond of VS clarity might retail for about $5000/ct. If the same diamond were of natural color, it would probably sell for more than $200,000/ct because natural green diamonds are unusually rare. In May 2016, a 5.03-carat VS2 fancy vivid green diamond, the “Aurora Green,” was auctioned by Christie’s for $16.8 million or 3.3 million per carat.

If a stone is identified as enhanced or processed, it’s treated. Chapter 9 describes diamond treatments and gives some tips on detecting them.

The Koh-i-noor is a 105.6-carat Indian diamond found more than 700 years ago that is part of the British Crown Jewels. It was once said that whoever owned the ‘Koh-i-noor’ ruled the world. One of its owners, Sultan Baber, referred to it in his diary in 1526 as “the famous diamond of such value that it would pay half the expenses of the world” (The Diamond by George Blakey, p, 31).

In ancient times in India it was assumed that the diamond had supernatural powers because it was harder than any other material and could be used as a cutting tool. To them it was a symbol of strength, power and courage. India, incidentally, was the first place where diamonds were found. All of the oldest diamonds are from India.

Nontoxic: Diamond is safe to use in humans because it is nontoxic. This allows doctors and dentists to use lab-grown diamond, diamond coatings and particles for drilling and cutting tools, artificial body parts and chemotherapy patches.

Resistance to chemicals: Untreated diamonds are not damaged by any chemicals. The fact that diamonds are resistant to chemicals and are harder than any other gem makes them an ideal gemstone for everyday wear.

Excellent conductor of heat: Diamond’s thermal conductivity is higher than that of any other solid, which is why diamonds feel cool to the touch. This property makes them important as heat sinks (cooling agents) for lasers, electron- ics and industrial usage because it protects silicon and other semiconducting materials from overheating. This also allows instruments that measure heat conductivity to easily distinguish diamonds from glass and cubic zirconia.

Excellent electrical insulator: Non-blue diamond strongly resists electric current so it is very effective at blocking the flow of current. Blue diamond, however, gets its color from boron impurities which make it a semiconductor. Since diamond is both an electrical insulator and good conductor of heat, it is invaluable for appliances, cell phones and computers.

Ability to be an electrical conductor: When manmade diamond is doped with boron it can conduct electricity and be used to create an electrode-based system for water purification. Contaminated industrial wastewater can now be purified and disinfected without chemicals, thanks to boron-doped lab diamond electrodes.

Resistance to high temperatures: Diamond’s resistance to high temperatures permits jewelers to steam clean it and repair diamond jewelry using a torch, unlike many gems which must be removed during repairs.

Resistance to radiation: Diamond’s resistance to radiation damage, chemicals, and high temperatures makes it an ideal material for space exploration, defense programs, radiation detectors and transistors.

Superior brightness: Brightness is the amount of white light returned to a viewer. Diamond has a greater potential for brightness than any other natural gemstone because of its extreme hardness, adamantine luster, lack of color and high refractive index.

Impressive fire: Fire (dispersion) is the display of rainbow colors of light. Diamond’s dispersion of light is among the highest of any natural transparent gem (0.044).

It’s not just hype to say that diamonds are a girl’s best friend. They’re everybody’s friend thanks to their remarkable intrinsic properties.