Demystifying Diamond Buying - Pitfalls to Avoid and Smart Ways to Save

With so many online retailers, diamond prices are more transparent than ever. Or are they? A one carat round brilliant SI1 clarity G color GIA-certified diamond, for example, can range from around $4200 to $12,000! And those numbers only represent three different websites. While some of the difference is bound to be in the different companies’ markups, there are also ‘hidden’ differences in the quality of diamonds that would seem at first glance to be identical. In this post, let’s bust some myths and uncover the pitfalls of getting a deal on a diamond.

Trap #1 - Fluorescence

Did you know some diamonds are fluorescent? This isn’t something usually brought up when talking about the four Cs--our own post on the subject doesn’t cover it either. But this ‘invisible’ quality can have a big impact not only on price, but appearance! Though it’s usually only visible under a blacklight, and a faint blue fluorescence can even make a diamond with a lower color grade appear whiter, medium and strong fluorescence can make an otherwise high grade diamond look milky, foggy, or cloudy!

rough diamonds showing fluorescence

A pile of rough, uncut diamonds under a blacklight. The glowing ones exhibit the property of fluorescence.

Trap #2 - Cut

Yes, cut is one of the four Cs, but it’s the one that usually gets ignored. That’s a shame, because cut can have a bigger impact on the beauty of a diamond than color or clarity! Just a few percentage points off in either direction on one or more of the various ratios can impact how light is reflected from the stone. These ratios and angles appear on diamond grading certificates, but the average consumer likely doesn’t know what they mean or even what constitutes a ‘good’ or ‘ideal’ percentage or angle. Table size (the facet on the top of the stone) and pavilion depth (the bottom portion), for example, are expressed as a percentage of the total diameter and the total depth, respectively. A diamond with a too-deep pavilion is, first of all, going to have a smaller diameter than better-cut diamonds of the same weight. It will also be darker, with less sparkle because of light being lost out the bottom of the stone. The dark center so created is called a ‘nail head.’ A too-shallow diamond may look larger, but its sparkle will also suffer because the light doesn’t have enough space to bounce around inside the facets before escaping. This results in a ‘fisheye’ effect.

A diamond can even have a Good or Very Good cut, but be slightly off in proportion. This could make it more ‘roval’ than truly round or it could have a wavy, uneven girdle (the outside edge). Cut problems can make a diamond more difficult to set as well, and potentially more prone to chipping or breaking.

diamond depth comparison

The leftmost diamond is cut shallow and shows the fisheye effect. The center diamond is ideal cut, and the rightmost diamond is a deep diamond with a nail head spot in the center.


Trap #3 - Enhanced Diamonds and Lab Diamonds

There are so many options today that it’s easy to get confused by different terms. First, let’s look at natural versus enhanced. While various enhancements are accepted industry standard for many gemstones and some fancy colors of diamond, most high quality white diamonds are natural. But not all enhancements are created equal. Only a lab can tell if a diamond is HPHT treated, for example. This high pressure high temperature treatment is permanent and affects the color. It does reduce the price of the diamond comparable to an untreated one of the same quality but should not be considered a negative quality. Laser drilling is similar in that it is permanent, reduces the price relative to untreated diamonds, and is not considered negative. This technique improves clarity by using a tiny laser to reach and lighten or remove inclusions.

Watch out, though, for coated or fracture-filled diamonds. GIA will not even issue a grading report for such stones because these treatments are not considered stable or permanent. Coating refers to a layer of material deposited on a diamond’s surface to mask a poor color. Fracture-filling is the injection of glass to hide white feathers in a diamond and thus improve the clarity, but standard cleaning or repair practices can remove it. Both of these practices are deceptive and though they are required to be disclosed, some retailers may gloss over them to make the sale. Be informed and get a lab report if possible for large diamonds.

Further confusing matters are the use of words like ‘lab created diamonds.’ We’ll start with a recently popular stone that sometimes gets called this, the moissanite. Now, moissanite is not diamond, but it is created in a lab because the naturally-occurring version is extremely rare on Earth. With a hardness of 9.25 and comparable brilliance and fire to a diamond, moissanite is fast becoming a popular diamond substitute. It can even fool diamond testing devices, but its double refraction gives it away compared to singly refractive diamond. On the pro side, it is less expensive per carat as well. Be aware though that it has much less resale value, at least currently, and tends to have color, typically in the J-K range, so you will need to spring for the most expensive brands if you are interested in a more colorless stone.

Moissanite ring

This ring is set with moissanites. The ones pictured have a visible greenish-gray tint which may be seen in some moissanites.


But what about actual diamonds created in a lab? Creating true diamonds (which you may also see referred to as ‘engineered’ or ‘cultured’) made of nearly-pure carbon arranged in an exact crystal structure is not an easy or quick process and requires a high tech laboratory with precise controls. This means that lab diamonds that are chemically and structurally the same as mined diamonds are not much less expensive. You can expect to pay $4000 or more for that same SI1 G one carat round mentioned at the beginning of the article. Plus, because the process is meant to replicate how a diamond is made naturally, the resulting stones aren’t flawless, and come in a variety of clarity and color grades. The cuts can often be quite good, however.

Let me find you the stone of your dreams. Contact me today to begin your free design consultation.

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