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Cognac Diamonds

Black Diamonds






At G.P.Grant, our dedication to excellence extends beyond mere craftsmanship - it's a commitment to ethical responsibility and meticulous attention to detail.


Diamonds, measured in carats, derive their name from the carob seeds historically used as a weight reference. This unit stands as a cornerstone in determining diamond value, with each carat equivalent to 0.20 grams. At G.P.Grant, we offer an extensive selection of diamond solitaires across a broad range of carat weights, ensuring every discerning taste finds its perfect match.



In the world of diamonds, clarity is of paramount importance. Inclusions, natural imperfections within the stone, can significantly impact its quality. The clarity of a diamond is determined by the number, size, and position of these inclusions. Using the clarity chart, diamonds are classified from "Flawless, with no visible flaws even under magnification" to "Imperfect, with inclusions visible to the naked eye." At G.P.Grant, our diamonds undergo meticulous selection, ensuring only those that are flawless to the naked eye are chosen. This meticulous curation guarantees exceptional clarity, offering a truly exquisite experience for those who appreciate perfection.



The allure of a diamond reaches its pinnacle when it sparkles with flawless color. Evaluated on a scale from flawless "colorless" diamond to "near-colorless," the diamond's color grade plays a crucial role. At G.P.Grant, our diamonds are exclusively selected from the flawless "colorless" range, ensuring they possess a charming colorlessness. We strictly adhere to rigorous standards, accepting only diamonds with minimal or no fluorescence. As a result, a collection embodying purity and sophistication is created.



The cut of a diamond stands as the paramount factor, determining its symmetry and balance—never too high, never too flat—a surefire guarantee of unparalleled beauty. At G.P.Grant, our brilliant-cut diamonds, exceeding 0.30 carats on the GIA scale, proudly bear the classification of 'Very Good' or 'Excellent,' ensuring optimal brilliance and an unmatched sparkle.

For brilliant-cut center diamonds under 0.30 ct, as well as for fancy-cut center diamonds, G.P.Grant adheres to a stringent standard, accepting only grades ranging from 'Good' to 'Excellent.' This commitment to excellence ensures each diamond radiates a distinct allure and charm.


Expert curation

Behind every G.P.Grant diamond lies the expertise of our seasoned gemologists. Their discerning eye and unwavering commitment to quality ensure that each stone meets the highest standards of beauty and brilliance.


G.P.Grant meticulously sources its materials with a steadfast commitment to ethical, social, and environmental responsibility. We are dedicated to continuously enhancing our performance in these areas, ensuring that our practices align with the highest standards of sustainability and accountability.


At G.P.Grant, we celebrate nature's beauty by exclusively selecting natural gemstones for our jewelry creations. We firmly exclude synthetic and imitation materials from our collections. Our commitment extends to embracing traditional practices for stone treatments, ensuring that they adhere to historically accepted standards within the stone trade. We stand by our principle of preserving the integrity of gemstones, prohibiting any process that alters their composition or durability. Our dedication ensures that only treatments enhancing the value and beauty of the stones are accepted.

Rubies & Sapphires

For stones over 1 carat, G.P.Grant exclusively avoids heating treatment. However, heating is accepted for stones below 1 carat. The rationale behind heating treatment for rubies and sapphires lies in its ability to enhance color. Heating eliminates undesirable blue or brown tints in rubies, resulting in a more intense red color. Similarly, pale sapphires benefit from heat to intensify their hue, while dark sapphires lighten when exposed to heat. Importantly, after heating, the stone's color remains stable.



G.P.Grant exclusively accepts filling with colorless oil for emeralds, with resin filling not being permitted. The oil level is restricted to a minimal amount compared to industry standards: a maximum of 'minor' for faceted stones over 1 carat and a maximum of 'moderate' for un-faceted stones such as cabochons, beads, and engraved stones. Emeralds require oiling primarily because they naturally contain inclusions. Filling these surface-reaching inclusions with oil enhances the stone's transparency. Emerald oiling, a practice dating back to ancient times, remains relevant today. Importantly, oiling is a reversible process that does not harm or alter the stone. Stones with lower fill levels are considered more valuable.


Stone treatments and scientific advancements

Treatment methods and the capability to detect them progress over time. At G.P.Grant, stones undergo analysis by accredited laboratories, and their findings align with the latest scientific understanding.

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