Diamond Ring Buying Guide: How to Identify, Evaluate & Select The Best Diamonds & Diamond Jewelry, 8th Edition

By Renée Newman

The updated Diamond Ring Buying Guide: 8th Edition is a visual guide to diamond quality evaluation, lab-grown diamonds, fakes, gem treatments, cutting styles, gold, platinum, palladium, silver, alternative metals, settings, ring selection, diamond grading reports, gem care and buying tips. The information contained within will help buyers select the best diamonds and mounting for their budget and needs.

• Language: English
• Publisher: BookBaby
• Release date: Mar 17, 2020
• ISBN: 9780929975559

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1/Diamond Price Factors

There are 8 basic price factors for diamonds

Cut quality (Proportions, finish and light performance)

Color

Carat weight

Cutting style & stone shape

Clarity (Degree to which a stone is free from inclusions and blemishes)

Creator (Man or nature?)

Transparency (Degree to which a stone is clear, hazy or cloudy)

Treatment status (Untreated or treated? What type of treatment?)

Why the 4 Cs is No Longer an Adequate Pricing System

If you’ve heard about the 4 Cs of color, cut, clarity and carat weight as a way to gauge diamond value, you may be surprised that there are twice as many factors to consider. The 4 Cs system of valuing gems is a clever, convenient way to explain gem pricing but it’s limited in that it causes consumers to overlook the importance of cut quality, treatment status, transparency and source.

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.

Price Factors Explained

CUT QUALITY

Cut quality, also called make, usually refers to the proportions and finish of a stone. These affect brilliance, which is defined by the American Gem Society (AGS) as brightness with positive contrast effects. Brightness is the actual and/or perceived amount of light returned by a diamond. A brilliant diamond has a pleasing regular pattern of sharp, bright and dark areas.

Cut quality assessment involves two fundamental considerations:

1. Do you see brilliance all across the diamond when it is face up? (fig. 1.1) Diamond brilliance should not be interrupted by large dark areas or white donut-shaped circular areas. (figs. 1.4 – 1.6)

2. Are you paying for excess weight that reduces the face-up size? (fig. 1.6)

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%.

COLOR

Basically, the less color the higher the price (except for fancy colors). D is the highest and most rare colorless grade. As the grades descend toward Z, color increases and the price decreases. See the GIA (Gemological Institute of America) color grading scale below, which was developed in the 1950s. Brown and gray diamonds are graded on the same scale.

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.

CARAT WEIGHT

In most cases, the higher the carat weight category, the greater the per-carat price of the diamond. A carat is a unit of weight equaling 1/5 of a gram. The weight of small diamonds is frequently expressed in points, with one point equaling 0.01 carat.

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.

CUTTING STYLE & STONE SHAPE

Shapes such as rounds cost more than others like pear shapes and squares. The effect of shape on price depends on the stone size, demand and available supply.

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

The fewer, smaller and less noticeable the inclusions and blemishes, the higher the price. There are 11 GIA clarity grades. They are summarized in the table below:

Clarity grading is further discussed in Chapter 7.

CREATOR

Diamonds created by nature are called natural diamonds or mined diamonds. Diamonds created in a laboratory or factory are described as manmade, lab-grown, created or synthetic. As manmade diamonds have become more readily available, their prices have dropped significantly. Chapter 10 explains how lab-grown diamonds are made and tested and compares their benefits to those of natural diamonds.

TRANSPARENCY

The GIA and the book Gems by Robert Webster define transparency as the degree to which a gemstone transmits light. They list five categories of transparency:

Transparent: objects seen through the gemstone look clear and distinct

Semi-transparent: objects look slightly hazy or blurry through the stone

Translucent: diamond is cloudy and milky like frosted glass

Semi-translucent or semi-opaque: only a small fraction of light passes through the stone, mainly around the edges

Opaque: virtually no light can pass through the gemstone

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.

TREATMENT STATUS

Unlike colored gems, most diamonds are untreated. However, that is changing. Diamonds may undergo the following treatments to improve their clarity, color, transparency and marketability: fracture filling, laser drilling, irradiation, heating, high pressure and high temperature (HPHT) treatment and coating.

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.

2/Why Diamonds are so Prized

Diamonds are the world’s most expensive gems. You may wonder why since many other gems are more rare. Some say it is just because of marketing by companies such as DeBeers. If that were true, then why was the Koh-i-noor diamond so prized a few hundred years ago when marketing companies didn’t exist?

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.

Diamond’s Remarkable Properties

Superior hardness: Diamond’s carbon atoms have a strong interlocking atomic structure and are exceptionally close together. As a result, diamonds are the hardest natural substance, making them an invaluable industrial material for cutting, grinding, polishing and drilling and the most scratch-resistant gem.

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,