Carat Weight

In most cases, the higher the carat weight, the higher the price. When evaluating carat weight, it is important to understand the term, CTW, or carat total weight. If a diamond is labeled 1 CTW (carat total weight) that generally means there are a number of small stones which make up a combined total weight of 1 ct. (carat)

Now a 1 ct diamond, refers to the weight of one stone. A ring that has a 1 ct stone will be worth considerably more than a ring that has a 1 CTW of the same quality. It is helpful to think about diamonds in terms of the per-carat cost. In order to calculate the total cost of a diamond, this formula is helpful.

Carat Weight x Per-Carat Cost = Total Cost of the Stone

For example a 1.05 ct Round, 'G' color, 'VS2' clarity is $7,200 per carat, so 1.05 x $7,200 = $7,560.

Buy Diamonds Just Under Certain Key Weight Thresholds - 'Buying Shy'

Looking to save some money on the cost of that diamond? A great money-saving strategy is to buy your diamond just under certain key weight thresholds also known as 'Buying Shy'. For example, if you want a 1 ct diamond, you could buy a .92 ct diamond and save a few hundred to more than $1,000 (depending on the color and clarity).

In the 'Rapaport Diamond Report' (also know as the 'Rap Price') a .92 ct Round (6.3 mm), 'G' color, 'VS2' clarity is listed as $5,700 per carat or $5,244 for the diamond (Carat Weight x Per-Carat Cost = Total Cost of the Stone) and a 1 ct Round (6.6 mm), 'G' color, 'VS2' clarity is listed as $7,200 per carat or $7,200 for the diamond - the difference is $1,956. You would save almost $2,000 on buying a diamond with a very minimal difference in appearance i.e., the thickness of a business card! Below are a few key thresholds:

• .50 ct look for .46 - .49
• 1.0 ct look for .90 - .96
• 1.5 ct look for 1.4 - 1.45

Cut of a Diamond

The cut quality of a diamond can affect the price by as much as 30%-40%. To determine the cut quality of a diamond, you should always rely on an independent laboratory such as GIA or AGS to evaluate the stone and issue a 'Cut' grade. Below is a chart that compares the 'Cut' grade from both GIA and AGS. We recommend only purchasing diamonds with a GIA 'Cut' grade of 'Good' or better or AGS 'Cut' grade of '4' or better.

As an example of how 'Cut' can effect price, a 1 ct, 'F' color, 'VS2' clarity, with a GIA 'Cut' grade of 'Excellent' was recently listed for $11,733 and another diamond with the same exact weight, color and clarity, with a GIA 'Cut' grade of 'Good' was recently listed for $8,479, a difference of $3,254! That is the impact a quality 'Cut' can have on price.

Scale
GIA	Excellent		Very Good		Good		Fair			Poor
AGS	0	1		2	3	4	5	6	7		8	9	10

Since GIA and AGS Labs use different scales and methods, this represents DiamondWave's opinion as to the equivalence of the two grading systems.

How does Clarity affect cost?

Clarity refers to the amount of internal and external flaws on the diamond itself. These flaws are usually called inclusions or blemishes. Clearly, the fewer the flaws in the stone, the higher the price will be. However, a flawless diamond is quite rare and very costly. To see how Clarity affects cost, take a look at the price of a 1 ct diamond, 'F color from IF (Internally Flawless) to I2 (Imperfect).

Scale	Flawless - Internally Flawless		Very Very Slightly Imperfect		Very Slightly Imperfect		Slightly Imperfect		Imperfect
GIA	FL	IF	VVS1	VVS2	VS1	VS2	SI1	SI2	I1	I2	I3
AGS	0	1	2	3	4	5	6	7	8	9	10
Street Price		$11,500	$10,400	$9,600	$8,400	$7,700	$6,300	$5,300	$3,800	$2,600	$1,400

As you can see, Clarity has a great affect on the cost of a diamond. For engagement rings, we recommend SI1 or better when selecting your diamond.

Treatments

Most diamonds are untreated and their brilliance, color and beauty are completely natural. When a diamond is treated, the quality of the stone is artificially improved by changing one or several of its characteristics. Such treatments generally target color and purity, however it is important to understand that various treatments will impact the price and marketability of a stone.

The main advantage to buying a treated diamond is price. Diamonds that are treated are normally discounted by 25-30% or more. The following is a summary of various diamond treatments.

• Fracture Filling- This method improves the clarity and transparency of the stone by filling the cracks with a filling that makes the imperfections almost invisible. Fracture filling is also known as glass infilling and clarity enhancement.
• Laser Drilling- Dark inclusions or flaws in a diamond can be improved by drilling into the diamond surface and then bleaching out or chemically dissolving the inclusions with an etching fluid such as sulphuric acid. The drill holes are then usually filled with a refractive wax or synthetic resin. These filled holes can be affected if your diamond is ever subjected to heat or acid as often is the case when being set in jewelry.
• Coating- Coating refers to the application of a colored substance to the surface of the stone to improve the color grade. This coating can effectively hide a diamond's yellowish tinge. Normally, the coating is applied to the bottom (pavilion) of the stone.
• Irradiating Diamonds- Irradiated colored diamonds are genuine diamonds that show different colors after being exposed to a strong radiation treatment. The diamonds quickly becomes inert after the treatment has finished. The diamond is then heated to effect an overall coloration.
• High Pressure High Temperature Treatment (HPHT)- This is a process using heating to change the color of diamonds. The temperatures used to heat the stones are above 1900 degrees Celsius, under extreme pressure. It turns inexpensive brown diamonds into green, yellow, blue, red or pink stones.