Diamonds are graded on a color scale of D through Z, based on the degree of colorlessness.  Color Quality is critical because the more colorless the diamond the greater its rarity and value.  Although many diamonds appear colorless to the untrained eye the majority contain slight traces of yellow, brown or grey. At Boston Ring and Gem we adhere to the defined d to z scale of GIA/AGS laboratories.  Every stone is individually examined by our in-house gemologist to verify the accuracy of the grading reports and or quality documents that accompany it.  Since color grades are in fact a range each letter grade can further be sub-divided to better describe the value of a diamond, for example G+, G, G- the first represents a strong G closer to an F in color, the second G lower than the first grade and finally a G that is closer to an H but is still in the G range, each of these three stones is priced differently because of the variation of color within the range.


We recommend DEF colors for those who don’t want any trace of color, GHI for those who don’t mind a slight tint. For fancy shapes diamonds we recommend G color or better because fancy shapes do not mask color like a round brilliant diamond. Color is a matter of personal preference and nature is beautiful in all shades, For value oriented buyers we recommend higher colors over clarity, color being much more noticeable from a casual viewing distance than a clarity grade of VS2 or SI1.


The higher a diamonds clarity the more rare and valuable it is, clarity characteristics also make every diamond unique. It’s extremely unlikely that two diamonds have exactly the same clarity characteristic in identical locations.  Virtually all natural diamonds contain identifying characteristics most of them too small to see with the unaided eye.  Clarity characteristics are nature’s birthmarks and when viewed under magnification they may look like tiny clouds, crystals and feathers.  Diamonds that don’t reveal such features are categorized as flawless or internally flawless and are treasured for there extreme rarity.  Stones that do exhibit clarity characteristics are given a clarity grade based on the size, number, position, nature and color of the internal characteristic.  Gemologists use 4 words when viewing a diamond under 10x magnification and the words are “minute”, “minor”, “noticeable”, and “obvious.”


Clarity grades as low as SI2 are sometimes eye clean and offer tremendous value especially when they are cut to ideal proportions. Note that these clarity grades are based on the face up appearance of the stone, clarity grades are not determined from looking at a stone upside down, some VS2 and SI1 inclusions are sometimes visible upside down because of the reflections, this is not an accurate representation of the clarity.

All our diamonds are examined for the accuracy of there grading reports, clarity grades are also a range and are almost never alike, some SI1 are better than others, some VS2 are better than others, and therefore we us our guidelines for selecting stones insuring you get top graded stones. That means that 9 out of 10 stones are rejected based on undesirable clarity characteristics.


The American Ideal cut is the name given to a recommended range of best proportions for the round brilliant diamond.  To get maximum performance cutters must observe certain relationships between the different sections of the diamond.  These relationships are called proportions and they are expressed as angles and percentages.


A well-proportioned diamond will outperform any other stone even stones with higher color and or clarity.  The Cut is the key that unlocks the beauty that lies within.

Finish and symmetry are also important in unlocking the diamonds potential.  Symmetry is the exactness of shape and placement of facets. Finish is a term for several factors of craftsmanship, including the quality of the polish, the smoothness of each facet, the condition of the girdle, and the overall precision of workmanship.  For maximum brilliance, sharp scintillation and clear dispersion an excellent polish is essential.

And last is performance, a term that refers to a diamonds light output rather than its craftsmanship.  No matter how good a diamonds craftsmanship, it can fail to produce maximum brilliance and fire.

Carat Weight

A carat is a measure of weight; it is the equivalent of 1/5 of a gram:  1 carat = 0.20 grams

Carats are also broken down into points: 100 points =  1 carat/ 20 point = 0.20 carat

Carat weight is one factor in determining the value of a stone. The Prices per carat increases for the same color/clarity combinations as we get into larger carat weight categories. Stones that are on the high end of these weight categories carry a 5-15% premium because of their extreme desirability and value even with the additional premium, such as:

0.60 -0.69 carat, 1.25 – 1.49 carat, 1.70-1.99 carat, 2.50 – 2.99 carat, 3.50 – 3.99 carat, 4.50 – 4.99 carat


Performance is judged by three factors: Brilliance, Fire and Sparkle.

Brilliance is traditionally defined as the intensity, or brightness, of the light reflected to the eye.  But the definition will prove inadequate unless we address the crucial contrast variations of brilliance that distinguish fine stones from mediocre ones.  Fine make diamonds have areas of light and dark that gives the stone bright, lively, and high-contrast appearance.  Poorly cut stones, on the other hand, have a low-contrast glassy appearance.

Fire.  Sometimes called dispersion refers to the rainbow colors seen when a diamond refracts light.  Diamond fire is not just judged by the variety of colors but the broadness and vividness with which they emanate.

Sparkle.  Also known as scintillation, this term refers to the glitters of light seen in a diamond’s crown as either the stone, the light source, or observer moves. cut2

Tilt, durability, and weight ratio are the final criteria.  Not only is the face up view considered but tilting the stone to examine its optics at different viewing angles are also considered. Durability refers to the possibility of the diamond chipping or breaking due to its extremely thin girdle or other inner weaknesses. And weight ratio refers to the appearance and size of the diamond in relation to its weight. Diamonds have many areas for possible hidden weight sometimes affecting the overall face up appearance of the diamond, those areas include “painted” halves, bulging step cuts, bulging P1 facets in princess and other fancy shapes, and excessively thick girdles.  All of the criteria described above are used to select our diamonds, we us our knowledge to filter out the most valuable gems in the world.


Diamonds are fashioned into all shapes, round brilliant being the most popular second to square shapes like the princess cut or other modified square brilliants and step cuts.  There is plenty of room for taste when choosing a diamond, shape for instance is a matter of preference but beauty is more of a science and that is what we help you achieve, we have extensive experience selecting the finest cut from all shapes insuring that the diamonds that we sell are the most beautiful stones and most valuable in the world because its not just our profession its our passion.



The length of the lower girdle and star facets (the later determines the length of the upper girdle facet as well) are very important.  These parameters define the positions and areas of the star, upper girdle and lower girdle facets, which typically cover more than half the surface area of a round brilliant, therefore they must not be overlooked because variations in size causes variations in appearance.


Another important aspect of diamond cut: the orientation of upper and lower girdle facets.  In a standard round brilliant these facets are evenly spaced around a diamond.  Yet upper and lower girdle facets can also be polished so that they lean towards the bezel or pavilion main facets and away from each other, facets created in this manner are referred to by diamond cutters as “painted facets”.  Leaning these facets toward the bezel or pavilion main facets “painting” the facets results in a thicker girdle scalloping at the junctions between the halves, which yields a greater weight in the finished diamond for the same total depth.  “Digging out” or leaning the half facet positions the other way toward the junction between halves, causes the scalloping to change in the other direction, the thickness of the girdle scalloping at the junction between halves is smaller than the bezel main girdle thickness and yields a lower finished weight.

Grading Report

All our diamonds are accompanied by GIA or AGS grading reports and quality documents, not all grading documents are equal.  Stones with grading reports other than GIA or AGS trade at considerable discounts because of inflated color/clarity grades.  We strongly adhere to GIA/AGS standard for color and clarity grading.  We find these standards to be the strictest and most accurate in the industry.



All our diamonds are accompanied by GIA or AGS grading reports and quality documents, not all grading documents are equal.  Stones with grading reports other than GIA or AGS trade at considerable discounts because of inflated color/clarity grades.  We strongly adhere to GIA/AGS standard for color and clarity grading.  We find these standards to be the strictest and most accurate in the industry.



Fluorescence is a phenomenon that is common in diamonds, the presence of a trace element during the formation of the diamond crystal results in fluorescence.  When the stone is hit with high-energy UV rays the atoms are excited and the material emits its own light and glows.  Fluorescence can be blue, yellow, orange and white.  Blue fluorescence can sometimes be a positive characteristic in white diamonds, other color fluorescence are not generally good for white stones but are good for diamonds that are the same color as the color they fluoresce, so a fancy yellow with a yellow fluorescence can be a positive.

For higher color stones DEFGH, fluorescence gives the stone a milky white undesirable appearance, which greatly lowers its value.  In some cases fluorescence has a minimal impact on price.  Fluorescence adds value to lower color stones as it gives the stone a whiter brighter appearance, IJKLMN with very strong Blue Fluorescence trade at a premium.