Learning about diamonds is never enough. You can never say that you know everything about them. Their meaning, history and all the little things in-between are just as splendid as their sparkling beauty. In this article, we will take a different approach to their world and get you introduced to the most frequently used terms related to these precious rocks. Welcome to our special-edition diamond glossary destined to all of you obsessed with the magnificence of “the girl’s best friend”.
Abraded Facets – scratches on the diamond’s surface caused by an error during the cutting process or if the diamond gets in contact with other diamonds or gemstones. In the first case, abrasion occurs if the cutting wheel gets too dry. It can be manifested as visible grayish abrasion or faint abrasion that is hard to locate in the stone. Abrasion can be fixed by removing the damaged material and re-polishing the facets.
Adamantine – a term used to describe the luster of diamond. It is also associated with gems whose refractive index (RI) is between 1.9 and 2.5. The root of this term is “adamant”, a word of Greek origin denoting something that cannot be tamed or broken. It is associated with the hardness of diamond, which enjoys a reputation of being the hardest mineral known to man.
Asscher Cut – an octagonal, step cut remarkable for its flawless symmetry. It features 74 facets and a high crown that are responsible for exhibiting outstanding dispersion and brilliance. The asscher cut was introduced to jewelry craftsmanship in 1902 by the renowned cutter Joseph Asscher.
Baguette Cut – a rectangular, step cut remarkable for its elongated look. The facets are arranged in a parallel, terrace-like pattern and they accentuate the boldness of the stone. The baguette cut is very similar to emerald cut, but it is mainly used for accent stones in ring designs. The word “baguette” has a French origin, referring to the traditional long and thin French bread. As the name suggests, this diamond cut is an invention of the French masterclass jewelers from the early 20th century, which is also known as the Art Deco period (1920’s – 1930’s).
Bezel Setting – a type of setting that fastens the stone with a metal rim surrounding it entirely. This setting creates a low profile for the diamond and enhances its protection; hence, it is highly recommended for people with active lifestyle.
Blemishes – flaws found on the surface of the diamond. They can be manifested as burns, polish lines and extra facets that may occur during the manufacturing process. The other type of blemishes are scratches, nicks and chips that usually occur during the mounting of the diamond, including wearing itself. Blemishes that are eye-clean do not affect the price and value of the diamond as those that are visible to the naked eye.
“Bow-Tie” Effect – a dark shadow reminiscent of a bow-tie that runs towards the center of the diamond. At certain cases, it is evaluated as a flaw; in others, it is considered an asset. The “bow-tie” effect occurs as a result of light obstruction while observing the stone from different angles.
Brilliance – the intensity of the reflections of white light transmitted through the top (crown) of the diamond. The overall light performance of a diamond comes as a result of several factors, including cut, clarity and polish as the major ones.
Bruted Girdle – unpolished girdle.
Carat – a unit of mass used for diamonds and gemstones. A metric “carat” is equal to 200 milligrams. This unit was officially adopted at the Fourth General Conference on Weights and Measures in 1907. “Carat” and “Carat Weight” are the two terms that represent the base of the ultimate diamond glossary.
Channel Setting – a type of setting where the diamond is set into a “channel” made with two parallel metal strips. Therefore, the channel-set stones form a clean and neat sparkling row with no metal between them. The channel setting is mainly used for accent stones to enhance the luster of the entire jewelry piece.
Clarity – the clarity of a diamond is expressed in “grades” that refer to the presence or absence of flaws (blemishes and inclusions) in the stone. A diamond’s scale of clarity includes 11 grading units, ranging from FL (flawless) to I3 (inclusions included and visible to the naked eye).
Cloud – a type of inclusion, typically a minor one.
Color – it refers to the type and intensity of color in a diamond. Depending on whether the stone is showcasing certain color tones or not, the color grading system varies from D (colorless) to Z (light color). The finest-quality diamonds, which are also the most expensive ones are colorless. The higher the presence of color in a white diamond, the lower its value.
Conflict-Free – a term used for ethically sourced diamonds. They have no connection to illegal selling, labor exploitation and terror/criminal activities. Conflict-free diamonds represent the revolutionary replacement for blood diamonds.
Crown – the upper part of the diamond above the girdle.
Culet – the tiny point at the tip of the diamond. It is where the facets of the pavilion meet and form a sharp point.
Cushion Cut – a pillow-like cut remarkable for its rounded edges. It can feature between 58 and 64 facets and it is one of the most aesthetic cuts of all. This cut is known for retaining the color of the stone, that is why it is primarily used in gemstone jewelry where high color grades are very appreciated. The cushion cut has been existing in jewelry craftsmanship for more than two centuries.
Dispersion – when light enters the diamond and separates into different spectral colors according to wavelength. Dispersion is responsible for the diamond’s capacity for fire.
Durability – the overall resistance of diamond, which is a combination of toughness, hardness and stability.
Eco-Friendly – a term that is usually used as a qualifier of lab-grown diamonds to denote their harmlessness to the eco system. “Eco-friendly” goes hand-in-hand with “conflict-free”, both promoting the ethical use of diamonds.
Emerald Cut - a rectangular, step cut remarkable for its long, open table and the emission of broad flashes of light. It is the most desired shape to get the optical appearance of slender fingers accentuated with a big stone. The emerald-cut diamond is said to look like a mirror, that is why color and clarity are so important for its overall performance. It features 57 facets in total and it is incredibly popular in vintage jewelry designs.
Eye-Clean - a classifier used for diamonds that display no visible flaws to the naked eye. Usually, these are diamonds with Flawless (FL), Internally Flawless (IF), Very, Very Slightly Included (VVS1 and VVS2) and Very Slightly Included (VS1 and VS2) clarity grades.
Facet – a small, flat, polished surface of the diamond. Each diamond shape requires proper symmetry, depth, height and length of the facets, hence, the reason why cutting is regarded as the most appreciated artistry in the jewelry industry. Facets are commonly divided into two categories – pavilion facets and crown facets.
Fancy Color – a term used for colored diamonds. The rarest and most expensive fancy colors for diamonds are deeply saturated blue, green and pink. The grading chart for fancy diamond colors ranges from FL (Fancy Light) to FV (Fancy Vivid).
Fancy Cut – Any diamond shape other than the round brilliant. The most popular fancy cuts are cushion, princess, emerald, asscher, radiant, oval, marquise, pear and heart. They are usually applied to large stones that have many facets.
Finish – a term used to denote the final, faceted and polished look that a rough diamond has been given to. A diamond’s finish includes two features – polish and symmetry.
Fire – the flashes of colors exhibited by diamonds and gemstones. Fire occurs in a spectrum of rainbow colors, as a result of dispersion.
Fluorescence – the capacity of diamonds and gemstones to release visible light when illuminated by higher energy wavelengths, such as X-radiation and ultra-violet light.
Four Cs – a popular term used to describe the main characteristics of diamonds, including cut, carat, color and clarity, all starting with the letter “C”.
French Cut – a square, multifaceted stone with 9 cross-crown facets, remarkable for its “four-pointed star” look. The French cut is an excellent choice for antique jewelry with geometrical patterns, which is the reason why it was the most popular cut in the 17th century.
Gemstone – a piece of mineral (precious or semi-precious stone) that is cut and polished to get ready for jewelry use. A gemstone can be of an organic and inorganic nature. Organic gemstones are renewable and are formed from biological processes. Inorganic gemstones are actually, naturally occurring rocks and minerals.
Girdle – the thin perimeter of the diamond which represents a border between its upper and lower part (crown and pavilion). Most diamond settings are designed in a way to hold the stone around or exactly at the girdle. The girdle can be left rough (unpolished) or with a matte finish (faceted and polished).
Hardness – the ability of diamond to resist abrasion. The hardness of diamonds and gemstones is measured according to the Mohs’ scale of hardness that ranges from 1 (talc) to 10 (diamond).
Heart Shape – a type of cut with a heart-shaped outline, as the name clearly suggests. This cut is mainly used to infuse the feeling of love and romance into the design; that is why it is extremely favored for bridal jewelry and jewelry of promise. It features 56 to 58 facets and it is said to have joined the family of fancy cuts in the 16th century.
HPHT – a technical term that stands for High Pressure High Temperature. It is the most effective method to enhance the color of a diamond. For instance, a yellow diamond can turn completely white (colorless) when heated to temperatures of up to 2192 °F and under pressure of 79770 Psi. The HPHT method was invented in the 1960’s, but it officially got a commercial use in the 1990’s.
Inclusion – an internal flaw of a diamond that may or may not be visible to the unaided eye. Inclusions occur in the form of cavities, crystals, internal graining, fluids and gasses, which are all foreign materials that somehow, have found their way to the diamond’s inside before, during or after its development.
Internal Laser Drilling – a type of diamond treatment to improve the clarity of the stone by removing its inclusions. It is a relatively new method that uses a cutting-edge microscopic laser to cut and remove the clarity. Internal laser drilling is mainly performed on mined, natural diamonds with visible dark inclusions.
Irradiation – a type of diamond treatment that simulates the natural radiation of mined diamonds over the course of years. The ultimate goal of this treatment is to enhance the original color of diamond by “attacking” it with neutrons or electrons. Irradiation is mostly performed to obtain deeply saturated blue, green, yellow, red and pink hues.
Lab-Grown – diamonds that are made by man. They are grown in a laboratory under highly controlled conditions and they feature the same physical and chemical structure as their mined counterparts. Other popular terms for lab-grown diamonds are: “synthetic”, “man-made”, “cultured” and “simulated”. The earliest attempts to create a synthetic diamond were made in the late 19th century. A century later, the first gem-quality diamonds appeared on the marketplace. They stand for conflict-free and eco-friendly use.
Lozenge Cut – a rhombus-like cut that features sharp angles of less than 45°. The lozenge cut is rarely seen in modern jewelry and it is a part of the old-fashioned, antique designs. It is believed to be a diamond shape of French origin.
Marquise Cut – a type of cut with an elliptical outline, remarkable for its graceful look with captivating pointed ends. This diamond shape was invented in the first half of the 18th century, under the command of the French king Louis XV. It features 58 facets that are wider on the pavilion. The other popular names for marquise cut are: “navette”, “boat-shaped”, “football-shaped”, “eye-shaped”.
Melée – small diamonds that usually accentuate the center stone and add more sparkle to the entire jewelry piece. The most common melee style is pavé setting.
Mounting – the other name for “setting”. It is a portion of metal where the diamond is sitting securely in place.
Natural – rough, untreated and unpolished diamond. This term can also refer to the remaining outer skin of diamond that comes as a result of cutting and polishing.
Needle – a type of inclusion that typically forms in larger diamonds. As the name suggests, it is a needle-like deformity within the diamond, which in many cases, is considered a signature trait and a benefit, instead of drawback.
Nick – a slight chip on the diamond’s surface that is commonly found around the girdle.
Old Mine Cut - a type of diamond cut remarkable for its small table, high crown and large culet. The old mine cut is the primary, unsophisticated version of the round brilliant cut that appeared in the 18th century. It features 58 facets and a distinctive hexagonal look, which gives it its second popular name “the triple cut”.
Oval Cut – a type of fancy cut, remarkable for its elongated shape that creates an optical illusion of a bigger stone. The oval cut was introduced in 1957 by Lazare Kaplan, one of the world’s most renowned diamond cutters. It features 57 facets that exhibit high grades of fire and brilliance when shaped into a perfectly symmetrical design. Oval diamonds are also known for the “bow-tie effect”, which also occurs in marquise and pear-shaped diamonds.
Pavilion – the bottom part of the diamond, right below the girdle. The facets in the pavilion function as mirrors and they have the highest refractive index of all facets making part of the stone’s physical structure.
Pear Cut – a type of fancy cut, remarkable for its teardrop look with a tapered point on one end. The pear cut is a mixture of the round and the marquise shape, because it combines elements of both styles. It features between 56 and 58 facets that optimize light reflection within the stone. This cut appeared in the 15th century, introduced by Lodewyk van Bercken, a renowned Flemish cutter and jeweler.
Phosphorescence – a phenomenon that occurs in fluorescent diamonds. When the stone is exposed to ultraviolet light for a longer period of time, it continues to glow for a while. This is what is called phosphorescence.
Point – a unit of mass used for diamonds and gemstones. One carat is divided into 100 points, which means that one point is 1/100th of a carat.
Polish – the smooth, silky finish of the diamond’s facets. The quality of the polish is critical for the stone’s brilliance and glass-like look. Once the diamond is given a particular shape, it is ready for polishing. This is the last process in diamond handling before the stone is mounted on a piece of metal.
Princess Cut – a type of fancy cut, remarkable for its inverted-pyramid look with four beveled sides and pointed corners. This is the second most popular cut, right after the round brilliant. It features between 57 to 76 facets and it includes elements of barion and quadrillion cuts. The princess cut was invented in 1979 by Israel Itzkowitz and it is highly recommended for long fingers.
Radiance – the amount of emitted and refracted light in the diamond.
Radiant Cut – a type of square, fancy cut, remarkable for the extraordinary level of white light (sparkle) reflected back to the observer’s eye. It usually features 77 facets, out of which those with trimmed edges are the cut’s signature mark. The radiant cut was invented in 1977 by Henry Grossbard. This is the first cut in history whose brilliant-facet pattern is applied to both the pavilion and crown. Radiant cut is also known for hiding the inclusions very well.
Reflection – the light that hits the stone and immediately bounces back up, thus providing it with an outstanding brilliance. Reflection also occurs when light hits specific inclusions within the diamond.
Refraction – the change of direction and speed of light passing from one medium to another. As light moves through the stone, it gets fractured and scattered, thus creating the one-of-a-kind sparkle that the diamond is best known for.
Refractive Index – the unit for measuring the speed (velocity) of visible light passing through the stone. Each type of precious and semi-precious stone has a specific refractive index (RI). For instance, the refractive index of diamond is 2.4175, which is a great number in terms of refractiveness. The refractive index of sapphire, for example, is 1.77, which is significantly lower than diamond.
Rose Cut – a type of diamond cut remarkable for its minimal circular outline, resembling to the narrowing spiral of rose petals. It features only 24 facets and a flat bottom with a dome-topped design. The rose cut is particularly desired in antique and vintage-inspired jewelry, known for being shiny, but not brilliant as some other types of diamond cuts, like the round brilliant, for example. It is believed that the rose cut appeared at the end of the 16th century and that its earliest version featured 6 facets in total.
Round Brilliant Cut – a type of diamond cut with circular outline, remarkable for the incredible grades of fire and brilliance it offers the stone. This is the most in-demand diamond shape for classic jewelry, adapted to meet the concept of modern beauty. It features 58 facets (33 on the crown and 25 on the pavilion) and it was introduced to the diamond cutting industry in 1919 by Marcel Tolkowsky.
Saturation – a term used to describe color intensity. For instance, a diamond with vivid blue color is showcasing a blue hue with very strong saturation. “Strong” stands for pure diamond color with no visible grayish or brownish tints.
Scintillation – a popular term used to denote the sparkle of diamond. Scintillation describes the play of white and colored beams of light occurring when the stone is viewed in motion. This is one of the most important and at the same time, most desired features of diamond. There are two main types of scintillation - fire scintillation and flash scintillation.
Solitaire – a term describing a jewelry piece that is bedecked with one precious stone only. It is considered a popular setting style, hence the term “solitaire setting”.
Step Cut – a type of cut where the facets are set parallel to the girdle. Diamonds that are given a step cut are usually square or rectangular, such as emerald, baguette and asscher. They are all admired for their large facets and extraordinary clarity that promote the so-called “hall of mirrors” effect.
Symmetry – a term used to describe the unified look of the diamond. More precisely, it refers to the precision of the cut and the symmetrical arrangement of the facets. The grades for a diamond’s symmetry range from “excellent” to “poor”.
Synthetic – one of the terms used for lab-grown diamonds.
Table – the horizontal facet on the top of the diamond. The table is located on the crown of a diamond and it is the largest facet of all. It has to be cut with the right proportions, because if not, it will affect the stone’s capacity for fire and brilliance, including its overall appearance. For example, the table of the perfectly-cut round brilliant diamond has an octagonal shape.
Tone – a variation of a diamond’s basic color. It is an attribute that denotes the lightness or darkness of the color. The other popular name for tone is “tint”.
Toughness – the ability of diamond to resist being fractured (chipping, cracking and breaking). The level of toughness denotes how well the stone can handle mechanical stress, for example, the impact of falling and hitting the ground. The scale of toughness ranges from “exceptional” to “poor”.
Transparency – the degree to which the stone transmits light, referring to both diamonds and gemstones. Transparency is affected by the texture of the stone’s material and the presence or absence of inclusions. The scale of transparency ranges from “transparent” (the most preferred one) to “opaque”.
Triangle Cut – a type of fancy cut, remarkable for its triangular look with sharp corners. The other popular terms for this cut are “trillion”, “trillium” and “trilliant”. Modern versions of the triangle cut include equilateral triangles (all three sides feature the same length), isosceles triangles (only two sides feature the same length) and scalene triangles (all three sides feature a different length). The triangle cut joined the family of fancy cuts in the 1950’s.
Ultraviolet Light – a type of light that cannot be seen with the naked eye, as it occurs as an electromagnetic radiation. When a diamond is exposed to UV rays, it becomes fluorescent.