Diamond Education

When it’s time to choose the ideal diamond for you we offer the finest GIA certified stones in Boston. We have a vast array of shapes and sizes for every taste and budget. Whether you are familiar with diamond jewelry or just starting to research diamonds, our knowledgeable staff will guide you through the process. We specialize in ideal cut round diamonds and uniquely brilliant fancy shapes.We guarantee that your search for the perfect diamond ends at Alex & Co.

The value of a diamond is largely determined by clarity, color, and carat, and the various grades within each of those categories. At Alex & Co. we understand that a diamond is an investment, and we take the time to educate and guide you through the decision-making process. Our Master Jeweler and GIA Graduate Gemologist has years of experience hand-selecting the highest quality diamonds in each category, which enables us to share helpful insights and advanced knowledge with you, so that you can maximize your budget and enjoy the ultimate value in a diamond.

Before you purchase, we want you to feel 100% confident with your decision and we believe that begins with being an educated buyer. We created this online diamond value calculator to enable you to easily explore your options and see firsthand how prices are affected by shape, clarity, color, and carat weight. Follow the prompts below to calculate diamond value based on the different grades you select.

For further assistance, please visit our Newton location where we stock a large inventory of sparkling diamonds for all budgets. We will gladly share side-by-side comparisons and assist you in finding your perfect diamond.

shape
clarity
Flawless Internally Flawless Very, Very Slightly Included Very Slightly Included Slightly Included Included
color
Colorless Near Colorless Faint Very Light Light
carat
arrow-left arrow-right
clarity

FL

Flawless

No inclusions and no blemishes visible to a skilled grader using 10x magnification.

IF

Internally Flawless

No inclusions and only blemishes are visible to a skilled grader using 10x magnification.

VVS1

Very, Very Slightly Included

Minute inclusions that range from extremely difficult to very difficult to see are visible to a skilled grader using 10x magnification.

VVS2

Very, Very Slightly Included

Minute inclusions that range from extremely difficult to very difficult to see are visible to a skilled grader using 10x magnification.

VS1

Very Slightly Included

Minor inclusions that range from difficult to somewhat easy to see are visible to a skilled grader using 10x magnification.

VS2

Very Slightly Included

Minor inclusions that range from difficult to somewhat easy to see are visible to a skilled grader using 10x magnification.

SI1

Slightly Included

Noticeable inclusions that range from easy to very easy to see are visible to a skilled grader using 10x magnification.

SI2

Slightly Included

Noticeable inclusions that range from easy to very easy to see are visible to a skilled grader using 10x magnification.

I1

Included

Obvious inclusions are visible to a skilled grader using 10x magnification and may affect transparency and brilliance.

I2

Included

Obvious inclusions are visible to a skilled grader using 10x magnification and may affect transparency and brilliance.

I3

Included

Obvious inclusions are visible to a skilled grader using 10x magnification and may affect transparency and brilliance.

GIA Clarity Scale
FL
IF
VVS1
VVS2
VS1
VS2
SI1
SI2
I1
I2
I3
Flawless Internally Flawless Very, Very Slightly Included Very Slightly Included Slightly Included Included
color

Colorless (D)

GIA Color Scale
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Colorless Near Colorless Faint Very Light Light
carat

The price of a diamond is generally calculated by its clarity, color, and carat weight, as illustrated with our diamond value calculator. The other major impactor of a diamond’s value is the quality of the cut—its proportions, brightness, fire, and scintillation—which, together with clarity, color, and carat make up the 4Cs. Other factors that affect the value of a diamond include diamond material and the presence of fluorescence in the diamond. To account for such characteristics that are unique to each diamond, our diamond calculator presents a range of prices.

To receive in-person guidance beyond the 4Cs from trusted and experienced jewelers, we welcome you to our Newton location. Please schedule an appointment to learn more about diamonds and see the precise differences, and all your options, firsthand.

The cut of a diamond refers to its proportions. Despite popular misconception, a diamond’s cut is not the same thing as its shape.

Every shape of diamond has different grades of cuts and it is the cut of a diamond that is most representative of its beauty, brilliance, and value. The cut is also the most technically difficult to pinpoint and requires precise analysis and state-of-the-art technology to accurately assess. However, while it takes expert knowledge and advanced tools to analyze the quality of a diamond’s cut, the naked eye can notice differences in light performance from one diamond to another, which is a key indication of the quality of the diamond’s cut. The better the cut, the more magnificently a diamond sparkles.

In order to determine the cut of a diamond, jewelers and gemstone experts, such as our Master Jeweller and GIA Graduate Gemologist, use the GIA Diamond Cut Scale to measure brightness, fire, and scintillation.

Brightness refers to the internal and external white light reflected from a diamond.

Fire refers to the dispersion of a diamond’s light into all the colors of the rainbow.

Scintillation refers to the amount of sparkle that a diamond produces, and the flashes of light and patterns of light and dark noticeable when a diamond is moved.

Before determining the final cut grade of any given diamond, the design and craftsmanship of the diamond is also assessed. This includes consideration of the diamond’s weight in relation to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

The GIA Diamond Cut Scale for standard round brilliant diamonds contains five grades, which range from Excellent to Poor, as seen on the Cut Grade example below.

Within each grade there are ranges of quality and we are known for hand-selecting the highest quality diamonds available. We take pride in offering only the finest and most spectacular diamonds in each grade at very competitive prices, to ensure that you receive optimal value for your investment.


Diamonds are formed in the earth over millions of years. Intense heat and thousands of pounds of pressure cause carbon atoms to crystallise and, as such, diamonds are naturally created. As with any truly natural occurrence, the color of every diamond will inherently differ very slightly. 

The naked, untrained eye typically has a hard time noticing the slight color variations, especially when it comes to high-quality diamonds with brilliant sparkle. There are, however, subtle differences in the natural color of diamonds that contribute to the value of each diamond.

The value of a diamond is influenced by how close it comes to being truly colorless. This is determined using a D-Z color-grading scale outlined by the GIA as the industry standard in diamond color grading. The exception of course being when there is a shade of color in the diamond that is yellow or brown, as that is not part of the D-Z diamond color grade. 

Our GIA Graduate Gemologist is highly experienced in assessing the natural color of diamonds and precisely pinpointing diamonds with the most brilliant color within each grade. This enables us to find you the most brilliant diamond and best value for your investment, within your price range. Visit our Newton location to view Boston’s most spectacular diamond collection and compare diamonds side-by-side.


Diamond clarity refers to the measure of blemishes present and the overall flawlessness of a diamond. Although no diamond is 100% pure, the closer the diamond comes to being flawless on the GIA Clarity Scale, the higher its value.

Due to the natural occurrence of diamonds in the earth and the inherent characteristics that result from the extreme heat and pressure that created them, all diamonds have unique internal characteristics. These internal characteristics are known as inclusions. External characteristics found on diamonds are known as blemishes. The extent of inclusions and blemishes in any given diamond are what determine diamond clarity.

Diamond clarity is assessed at 10x magnification, as many inclusions aren’t visible to the naked eye. Even diamonds that have been classified as flawless may have visible inclusions at higher magnifications.

In order to accurately evaluate the clarity of a diamond, a gemologist reviews the number, size, relief, nature, and position of the inclusions and blemishes, to determine where the diamond falls on the GIA International Diamond Grading System. The diamond is then assigned a clarity grade that ranges from diamonds that are virtually Flawless (FL), to diamonds with obvious inclusions (I3). Discounted, less favorable diamonds will typically have less desirable characteristics that are not mentioned on the diamond report, such as those with black inclusions, or a milky appearance.

Even though many inclusions and blemishes are too small to be evident to the naked eye, they still affect the price of diamonds. That said, unless a diamond is heavily included, small internal and external characteristics have no effect on a diamond’s ability to reflect light and sparkle radiantly.

As Boston’s premier diamond jeweler, we proudly offer the most beautiful and radiant selection of diamonds available for every budget and style preference, regardless of their clarity rating.

The shape of a diamond, or other precious and semi-precious gemstones, forms the focal point of your jewelry, and we believe the shape you select should represent your individual style, personality, and story.

The most popular shape is the round brilliant cut, followed by the princess cut (which is square), and the cushion cut (which is square with rounded edges). Other prominent shapes are the radiant cut, asscher cut, oval cut, emerald cut, pear cut, marquise cut, and heart-shaped cut. The illustrations above provide a side-by-side comparison of the most popular gemstone shapes to assist you in determining your preference.

At Alex & Co. we showcase an extensive collection of diamonds and other precious and semi-precious gemstones in all shapes and sizes. Our experienced Master Jeweler and GIA Certified Gemologist take care to hand-select the highest quality and best-shaped stones, to provide you with a variety of options to suit your taste and your budget.

We will work with you on the selection process and find the best value for your budget, in the specific gemstone shape you enjoy most. Each piece of fine jewelry in our designer collection is fitted with the best-shaped stone to maximize the piece’s brilliance, and we will gladly advise you on the most complementary setting for your selected shape. Our jewelry artisans can also custom-design jewelry for you around your desired shape, and create a piece that is entirely your own.

Fluorescence refers to the visible light which some diamonds emit when they are exposed to invisible ultraviolet (UV) rays. On a GIA Diamond Grading report, fluorescence indicates the strength or intensity of the diamond’s reaction to long-wave UV rays, which is an essential component of daylight. The light emitted lasts as long as the diamond is exposed to the ultraviolet source.

Not all diamonds exhibit fluorescence, but it is a relatively common occurrence in brilliant diamonds. Of all diamonds submitted to GIA over the past decade, approximately 25% to 35% exhibit some degree of fluorescence. However, only 10% of those diamonds showed strengths of fluorescence that may impact the diamond’s appearance; that is, showed strengths noted on laboratory reports as medium, strong or very strong. In more than 95% of the diamonds that exhibit fluorescence, the color seen is blue. In rare instances the reaction is yellow, white, or another color.

GIA studies show that for the overwhelming majority of cases, the strength of fluorescence in a diamond has no widely noticeable effect on a diamond’s appearance. In many instances, observers prefer the appearance of diamonds that have medium to strong fluorescence, but in rare cases, diamonds with extremely strong fluorescence may appear hazy or oily (fewer than 0.2% of the fluorescent diamonds submitted to the GIA exhibit this effect.)

Fluorescence does not compromise the structural integrity of diamonds. A diamond that fluoresces has the same integrity as a diamond that exhibits no reaction to UV rays. Submicroscopic substitutions and/or shifts in a diamond’s structure can cause fluorescence, as well as prevent it. Nothing in either instance inherently weakens, or is bad for, the diamond.

For more information about fluorescence and to compare diamonds side-by-side, please visit our Newton location where our artisan jewelers will gladly assist you.