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Most retailers talk only about the "4C's," but at Mavilo,  we believe that cost should be an additional factor to evaluate when you are considering a diamond, because it is such a significant purchase However, it's important to understand that it's not only about finding the lowest price, but also what you are actually getting for your money. Since there are no specific published cost guidelines available to the general public, we suggest taking the following points into account:

The Source

  • Is the seller you are considering an importer or a wholesaler?
  • Does the seller actually OWN the inventory?
  • Is the seller just presenting options from a virtual diamond inventory?
  • Has the seller examined the actual diamond to evaluate the significance of any inclusions and other characteristics?
  • Do they sell enough volume to be able to offer high quality at low prices?
  • Does the seller ascribe to ethical sourcing practices?

The Diamond Report

The Rapaport Diamond Report is a report and price sheet that serves as the industry-wide standard for diamond costing. It also includes news on the industry and how it could impact diamond prices. Cutters and dealers all over the world use this report as a reference when trading diamonds. Pricing can vary according to certain premium sizes, colors and shapes. This monthly publication of wholesale prices is not available to the general public, but is an important factor in determining true wholesale market values. The best analogy for this report is the "Blue Book" used when purchasing an automobile. At Mavilo, we price our diamonds according to the latest Rapaport Diamond Report, which reflects the latest discounted wholesale market prices, not by determining a contrived “Retail Value” with no real market basis, and by doing so we are able to pass the savings on to you. Our ability to offer market-based wholesale pricing direct to our customers has been the cornerstone of our success.


It is imperative that an independent gemological laboratory grade and identify any diamond you are considering purchasing, in order to determine its exact quality. Inaccurate grading could dramatically affect perceived value, so the certification should come from a trusted name, a laboratory that maintains the highest standards and that has no financial interest in the diamond. Certifications are official documentations that protect your investment. There are currently three internationally recognized laboratories, as well as local independent gem labs that are qualified to issue certifications:


While nature determines a diamond.s color, clarity and size, a master diamond cutter is needed to bring out its full radiance, releasing the fire and brilliance. The cut and proportions are what enhance a diamond.s ability to reflect the maximum amount of light; therefore cut is a key factor in ultimately determining the brilliance and value of a diamond.

The cut of a diamond has three attributes: brightness (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the light flashes – or sparkle – when a diamond moves).


Since the proportion of a diamond cut affects beauty and value, it's important to be familiar with the vocabulary the industry uses to help determine the quality of a cut. For example, below is a side view of the standard round brilliant. The major components, from top to bottom, are the crown, the girdle, and the pavilion. A round brilliant cut diamond can have either 57 or 58 facets, depending on whether or not the culet, a tiny flat facet at the bottom of the pavilion, is included or excluded. The large, flat facet on the top is the table. The proportions of a diamond refer to the relationships between table size, crown angle, and pavilion depth.

Ideal & Premium Cuts

An understanding of diamond cut begins with the shape of a diamond, with the standard round brilliant dominating the majority of diamond jewelry. All other diamond shapes are known as fancy shapes or fancy cuts. For detailed specifications on shape and cut, see our Fancy Cut Diamonds section.

Round Cut

In 1919, Marcel Tolkowsky, an engineer and member of a prominent Belgian family of diamond cutters, developed the Ideal Cut for round brilliant diamonds, which subsequently became the standard in North America. Tolkowsky's book, Diamond Design, is a mathematical and optical analysis of the dispersion and behavior of light in diamonds, outlining his observations and the parameters for the Ideal Cut. Tolkowsky's Ideal Cut remains the benchmark for cut quality nearly a century later.

A well-cut diamond will be considerably more beautiful and valuable than a poorly cut stone of the same size, clarity and color.

When a diamond is well cut, light enters through the table and travels to the pavilion where it reflects from one side to the other before reflecting back out of the diamond through the table and to the observer's eye.

In a poorly cut diamond, the light that enters through the table reaches the facets and then 'leaks' out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less brilliance

Light Reflection and Diamond Cuts

Cut Grades

Diamond cut is notoriously difficult to analyze, but GIA and AGS have several grading techniques that have been developed to help consumers determine the classification of a particular diamond. In general, these grades are: Excellent, Very Good, Good, Fair and Poor.


Although to the untrained eye most diamonds appear white, the color of a diamond varies tremendously, and the closer it approaches “colorless,” the more valuable it is.* A diamond's color is determined when it is first formed, deep within the earth, and never changes over time. Chemical impurities, like traces of other elements, may have been incorporated into the overall composition, which affect the hue by adding a brownish or yellowish tint.

The industry standard for grading 'whiteness' or colorlessness is the GIA Diamond Color-Grading Scale. The scale begins with the highest rating of D for colorless, and continues, with increasing presence of color; to the letter Z. Diamonds are color-graded by comparing them to stones of known color under controlled lighting and precise viewing conditions. A single change in color grade can significantly impact a diamond's value.

Diamonds graded D through F, or colorless are the most valuable and desirable for their superior light refraction and for their rarity. Only one-fourth of the total number of diamonds found can be graded colorless. However, diamonds graded G through I show virtually no color to the untrained eye. When deciding on a color grade for your diamond, consider the setting that will complement the stone – if your setting is white gold or platinum, the degree of colorlessness will be more visible than if you choose yellow or rose gold.

Fluorescence (The black light effect)

Another term you may come across when evaluating color is fluorescence, or photo-luminescence. This is an effect that is seen in some gem-quality diamonds when they are exposed to long-wave ultraviolet light, similar to when white objects glow under the effect of a black light. Fluorescence is caused by a trace amount of the element boron found in the diamond. Under most lighting conditions, fluorescence is not detectable to the naked eye. While most gemologists prefer diamonds without this effect, others find it desirable.

*The exception to this rule is fancy-colored diamonds, found in vivid reds, blues, pinks, greens and bright yellows. Fancy-colored diamonds are extremely rare and highly prized.


Clarity is the measure of naturally occurring features known as inclusions, and is an indication of a diamond's purity. Almost all diamonds have inclusions, which are like “fingerprints” or “birthmarks” that appear when diamonds are formed within the earth. Traces of minerals, gasses or other elements are trapped inside during the crystallization process, and result in these impurities. Often not visible to the naked eye, inclusions can appear as tiny crystals, clouds or feathers.

Diamonds are graded using a 10X loupe, a lens that magnifies objects to ten times their actual size, so that identifying characteristics can be evaluated with the highest precision. The position of inclusions has a significant effect on the value of a diamond; some can be concealed by a mounting, having little effect on overall beauty. However, an inclusion in the middle or top of a diamond could impact the dispersion of light, rendering the diamond less brilliant. Diamonds with very few birthmarks are extremely rare and, of course, rarity affects a diamond.s value. In fact, less than 1% of all diamonds have been found to have no inclusions and can be called flawless.

The clarity of a diamond is graded by the number, size, nature, position, color, quantity and visibility of inclusions under 10X magnification. The standard measure used is the International Diamond Grading System¢â, created by GIA. Diamonds are given a clarity grade that ranges from flawless (FL) to diamonds with more prominent inclusions (I3). The GIA Clarity Scale designates 11 grades, with most readily available diamonds falling into the VS or SI categories.

Mavilo only sells diamonds graded Internally Flawless (IF) through Slightly Included (SI) because of our extremely high standards in selecting and buying our diamonds.


A carat is the universal measure of weight (not size!) for a diamond, and is the easiest of the 4C's to determine. One carat is equivalent to 200 milligrams.

Because even a fraction of a carat can represent a considerable cost difference, exact precision is essential. In the diamond industry, weight is measured to a thousandth of a carat and rounded to the nearest hundredth. Each hundredth is called a point (a 0.25 ct. diamond is 25-points.) Diamond weights greater than one carat are expressed in carats and decimals (a one and a half carat diamond is 1.50 ct.) A 0.75 carat diamond is the same as a 75-points or 3/4 carat diamond.

Some weights, in particular one carat and one and a half carat, are considered "magic sizes" – this is because there is a significant jump in price for these preferred sizes.