How to Buy Diamonds


Considerations When You Are In the Market to Buy Diamonds

As the president of Hamilton York Estate Buyers, I have purchased millions and millions of dollars worth of diamonds over the years and am going to share with you some key components of a diamond and the traits to avoid when choosing a stone. The information in this diamond guide will outline the many considerations you must account for when you are in the market to buy diamonds. My diamond buying guide will help you purchase a quality stone and avoid purchasing a "problem stone" in the event you ever wish to sell your diamond to upgrade to a larger stone. Although your purchase will obviously include a piece of jewelry to hold the diamond, most of the money you spend will go towards the purchase of the main diamond.

Classic Four "C’s" of Diamonds:


This refers to the shape of the diamond such as Modern Round Brilliant, Princess Cut, Pear Shape, Asscher, Emerald Cut, Radiant, Marquise, Oval, Cushion, etc. and also to the proportions of the stone. In addition to the shape of the diamond, the Cut also can refer to the proportions of the stone. While the shape of the diamond is a personal choice, the proportions of the stone are extremely important and can have a dramatic effect on the value of a diamond. As an example, let’s assume that you wish to buy a 1.00 carat Modern Round Brilliant Diamond. Ideally this stone should have a diameter measurement of about 6.5 millimeters and a depth to width percentage of 60%. If the diamond only measure 6.3 millimeters in diameter, a larger percentage of the weight is in the pavilion (area beneath the maximum diameter/girdle) of the stone and it visually looks smaller when viewed from the top. Although the diamond still weighs 1.00 carat, it will not be worth the value of a properly cut diamond and therefore can be considered a "problem stone". When you buy diamonds, it is therefore very important that you know the proportions of the stone.


Non-fancy colored diamonds are graded on a scale from D-Z, with a "D" color being the whitest and a "Z" color having a very obvious degree of yellow hew to the stone. There is very little color difference between each color grade and to accurately color grade a diamond requires a set of "master" color diamonds to use for comparison. A diamond must be loose and not in a piece of jewelry to be accurately color graded. When you buy diamonds, the value of the stone is greatly impacted by the color grade and therefore it is very important that you know the exact color grade of the stone you are choosing. I recommend that you examine the diamond loose rather than in a piece of jewelry as the true body color of the diamond can only be determined from the side with the stone laying face down on a white surface.


The Clarity of a diamond refers to the amount of inclusions in a stone when viewed under 10x magnification. Although there are flawless diamonds, most diamonds do have some inclusions. The clarity scale is as follows: FL or IF, refers to Flawless and/or Internally Flawless. The only difference refers to minor degree of polish. The next step down the scale is VVS1 which means Very, Very, Slightly Included, followed by VVS2 then down the scale to VS1, VS2, SI1, SI2, I1, I2, and I3. It is this author’s opinion that a "smart money" stone to be worn every day should be chosen with a VS2 or SI1 clarity. These two clarity grades will have minor inclusions that should not be visible to the naked eye or interfere with the refraction of light through the stone. As a final note, there are basically two types of inclusions: white feathers and white or black crystals. It is preferable when you buy diamonds to choose a diamond which does not have black crystals for obvious reasons.

Carat Weight

This simply refers to the weight of the diamond. There are 100 "points" in a carat and typically a diamond is weighed to two decimal points such as 1.06 would mean a stone that weighed One hundred and six points, or one and six one hundredths carats. A carat is a measure of weight derived from the ancient practice of using carob seeds as a weight standard due to their relative uniform size and weight, but is now standardized as 1/5 of a gram. For obvious reasons, a diamond must be loose and not in a ring or other piece of jewelry to determine the exact carat weight using a carat scale.

Diamond Traits to Avoid

Now for the traits of a diamond to avoid when you are searching for the perfect diamond.


Although you may read a lot of conflicting opinions about this issue, I strongly advise that you avoid diamonds that exhibit very strong, strong, or medium fluorescence. The fluorescence of a diamond is caused by the presence of nitrogen in the stone and is exhibited when exposed to ultraviolet rays (a black light). About 25-35 percent of diamonds have some degree of fluorescence and will typically glow blue or yellow when exposed to these rays. Although a very interesting phenomenon, it can cause a diamond to have a milky appearance especially when exposed to sunlight which contains ultraviolet rays. Diamonds which have strong or very strong fluorescence are very heavily discounted in the world or diamond dealers. I highly recommend that when you buy diamonds that you choose a stone which has "none" or at the most, "faint" fluorescence.


There are several ways that mankind has invented to improve the appearance of a diamond. I highly recommend that when you buy diamonds, you avoid stones which contain any of the following enhancements. These include Laser Drilling, Fracture Filling, High Temperature-High Pressure treatment and Irradiation. It is this author’s opinion that these treatments are simply ways to fool the general public and should be disclosed by any dealer selling them. Unfortunately, some dealers do not agree and consumers end up paying for a treated diamond that is not worth anywhere near the price paid.


Although many people have heard of CZ, cubic zirconium, many are not aware that there are other man made stones that closely resemble the look of a diamond. The most recent of the man-made synthetics is Moissanite. This crystal actually exhibits a greater refractive index than a diamond and is a very beautiful synthetic stone. But it is not a diamond and is not worth anywhere near the price of a diamond. Although industrial diamonds have been man-made for many years, only in the last few years have true gem quality stones hit the market. Unfortunately, even the best diamond dealer may not be able to detect a manmade diamond and when suspect, should be sent to a legitimate lab such as GIA (Gemological Institute of America) for complete analysis. This author highly recommends that when you buy diamonds, that you have complete trust in the person you are purchasing the stone from.

Laboratory Grading Reports

There are numerous laboratory reports issued for diamonds. To be very blunt about this issue, I highly recommend that when you buy diamonds, that you insist that the stone is certified by GIA, the Gemological Institute of America. This non-for-profit college invented the diamond grading scale and issues the only grading report that is accepted around the world by diamond dealers as having the highest degree of accuracy and consistency.

I hope that this overview has been helpful for you to make a wise choice when you buy diamonds. Our next article, "How to Choose a Professional Diamond Buyer when you Wish to Sell Diamonds" will focus on the key issues when you wish to sell diamonds. This will be helpful if you choose to upgrade to a larger stone or if you inherit a stone and wish to sell it for cash.