Diamond Info

Diamonds symbolize eternal love and commitment—symbolically, structurally, and physically, each is a dichotomy of complexity and simplicity.

Spinelli Kilcollin is dedicated to providing you with your ideal diamond, specific to your requests and preferences. We work exclusively with round brilliant cut diamonds which are triple excellent quality, G color, and above SI1 clarity at minimum. We provide GIA certification for each of our white solitaire diamonds.

Founded in 1931, The Gemological Institute of America—or GIA—is the world’s most respected grading entity. GIA is a nonprofit institute at the forefront of gemological research and education, which aims to protect the buyers and sellers of precious gemstones by setting and maintaining standards of quality that surpass all other grading systems.

In 1953, GIA developed its International Diamond Grading System, and with it determined a methodology commonly referred to as the Four Cs system, which grades diamonds based on their cut, clarity, color, and carat weight. The Value of a diamond is determined almost entirely by where it stands on this specific grading rubric, which is explained below.


Cut is often considered to be the most important of the four C’s, as it is the primary determinant of a diamond's scintillation (sparkle) and brilliance. The cut of a diamond refers not to the diamond’s shape, but to the balance of proportion, symmetry, and polish achieved by the diamond cutter as the facets are created. A well-cut diamond can appear larger than a poorly-cut diamond of the same carat weight, and an apparent enhancement of both color and clarity can be achieved in cutting. Each individual rough diamond is examined and mapped so that its size can be maximized and its shape and clarity can be enhanced in the cutting process. The technique also draws on the unique characteristics of an individual diamond, so that its distinctive and idiosyncratic beauty is intensified. For peak light performance, an ideal cut is neither too shallow nor too deep. When cut at optimal angles, light is returned through the top of the diamond, which allows for the diamond to radiate and emanate more shine. When cut too shallow, light is lost from the bottom of the diamond, and if the cut is too deep light escapes from its sides.


The diamond color measurement of most gem-quality white diamonds is actually based on the absence of color: a chemically pure and structurally perfect diamond has no hue, and consequently, a higher value. Diamonds rated by GIA fall on a color-grading system, which ranges from ‘D-to-Z,’ and measures a stones degree of colorlessness. Many of these color distinctions are so subtle that they are invisible to the untrained eye, however they make an immense difference in the overall quality of a diamond, and to its ability to reflect light. Diamonds with less color allow more light to pass, and thus they release more brilliance.


A diamond is distinguished from others by its naturally occurring characteristics, which are determined by its clarity. Diamond clarity refers to the grading of the presence of inclusions and blemishes. Natural diamonds are the result of carbon that, when exposed to tremendous heat and pressure deep in the earth, forms into rough stones. The formation process can result in a variety of characteristics within the diamond, which are called ‘inclusions,’ and surface characteristics, which are referred to as ‘blemishes’: as a diamond is forming, small crystals can become trapped and imperfections can form. A diamonds clarity is determined and judged by the number and types of these characteristics, using a scale that ranges from I3 (which indicates that Included and visual flaws which can be seen by the naked eye are present) to FL (which indicates that the diamond is flawless). Graders use 10X magnification to identify the clarity, and to map any specific characteristics on “diamond plots.” These plots are essentially small, unique maps of the diamond that are used to identify each individual stone. No two diamonds will ever have the exact same internal pattern, so these plots work as a form of individual identification, much like a fingerprint. The quantity, size, color, location, orientation, and visibility of inclusions all affect the final clarity grade of a diamond: the clearer a stone is, the more brilliance it will emit. Rarely is a diamond entirely flawlessly clear.

Carat Weight

The carat weight of a diamond refers to its weight, and is a unique unit of measurement used exclusively for gemstones. A carat is equivalent to .2 grams or .007 of an ounce. Carat weight is unrelated to the similar-sounding ‘karat,’ which refers to the purity of gold. As with cut, carat weight establishes the visual size of the diamond—but when comparing diamonds, it’s important to keep in mind that increased carat weight may not necessarily mean that a diamond will appear visually larger. As the carat size of a diamond increases, so does the price of the diamond, as the larger the diamond the more increasingly rare it is. Fewer than one in one million mined rough stones are large enough to produce a finished 1 carat diamond!

Every diamond on earth has its own DNA, which makes it one of a kind and allows for us to classify it. Analogous to fingerprints, these characteristics symbolize the unique qualities we have as humans—a reminder of the fact that in order to something to be beautiful, it doesn’t need to be perfect.

We’ve cultivated relationships with diamond sellers who we trust, and who pay careful attention to the sourcing and quality of each of their diamonds. We guarantee stones which are Conflict Free and abide by the Kimberly Process. Read More here...

For those interested in more unique, perfectly imperfect diamonds, Spinelli Kilcollin Galaxy Diamonds are more individualistic and as beautiful as white diamonds.

Interested in something more modern? For those passionate about transparency and the development of technology in the industry, we also offer Cultivated Diamonds.

Gray Diamonds

Gray Diamonds, or colored diamonds, which we offer in our Galaxy Rings and in our Wedding Collection, are graded according to a different rubric than that of white diamonds. Gray diamonds are known and appreciated for their natural colors and character. Gray diamonds are in fact white diamonds that have numerous natural inclusions. The inclusions are not considered to be flaws—instead, they provide diamonds with celebrated darkness and character. Gray Diamonds can also contain carbon that has not crystallized, and the presence of this carbon creates the tonal darkness and complexity.

Cultivated Diamonds

Spinelli Kilcollin also works with cultivated Diamonds sourced through the Diamond Foundry. Diamond Foundry diamonds require the skill of human craftsmanship and precision. Rather than being mined from the ground, every diamond is grown by a highly skilled team in California. They are genuine diamonds which are anatomically and physically identical to mined diamonds. As with diamonds that form in the earth, each stone has its own unique growth pattern, imperfections, inclusions, and characteristics. No two cultivated diamonds are the same—just as with mined diamonds. The only difference between the two is their origin. The Diamond Foundry re-creates the conditions in which diamonds form under the earth in their California-based foundry. We work with these stones to give people the ability to choose the perfect stone(s), without sacrificing stone quality or individual, personal ethics. (Read more about our sustainability mission here...)