Glossary of Diamond Terms
Artisanal Mining - A smaller-scale form of mining conducted by individuals, groups, families or cooperatives with minimal or no mechanization.
Asscher Cut - A type of diamond cut with a square shape and cut corners, known for its large step facets and high crown that produce a brilliance unlike any other diamond shape. Patented by jeweler Charles Asscher in 1902.
Baguette Cut - A type of gem cut shaped like a small loaf or rectangle.
Band - The part of a ring that goes around the finger.
Bearded Girdle - Tiny, hair-like fractures that extend from the girdle surface into the stone.
Bezel Setting - A setting technique in which a metal rim fully or partially encircles the sides of a gemstone, securing it in place.
Birefringence or Double Refraction - The optical property of a mineral that produces a double image of an object viewed through it. Diamond is singly refractive, meaning light passing through the gem is not broken into two rays.
Brilliance - The brightness that comes from the reflection of light in a diamond. It's one of the most important characteristics that give a diamond its sparkle.
Brilliant Cut - A cutting style designed to maximize a diamond's brilliance. The most common brilliant cut is round.
Burnishing - A metalworking technique used to smooth the metal surface, often resulting in a mirror-like finish.
Cabochon - A gemstone that has been shaped and polished as opposed to faceted. It typically has a flat base and a rounded top.
Carat Weight - The standard unit of measurement for the weight of diamonds. One carat is equivalent to 200 milligrams.
Carbon Spots - An often-missused term implying that included crystals are visible in the diamond. In reality, included crystals are not always black, and they are not spots of carbon.
Cavity - An inclusion that is an actual hole or deep indentation in the diamond's surface.
Certification/Cert - A document you receive from a gemological lab that describes detailed characteristics of the diamond, such as color, clarity, and carat weight. Technically, it is a ‘diamond report’, not a certification, according to GIA (Gemological Institute of America).
Champagne Diamond - A type of diamond that has a light brown or yellow color, similar to a champagne color.
Channel Setting - A type of gemstone setting in which a number of small stones are set side by side in a grooved channel. No metal separates the stones, which creates a glittering row.
Clarity - One of the four Cs of diamonds, referring to the presence of inclusions or blemishes in a diamond.
Cleavage - One of the characteristics of a diamond is the tendency of crystalline minerals, like diamond, to split in certain directions where the atomic bonding is weak.
Cluster Setting - A setting style that clusters many stones together, often around a larger center stone.
Colored Stones - This term refers to gemstones that exhibit color, which can be anything from sapphires, rubies, and emeralds to semi-precious stones like amethyst, citrine, and garnet.
Conflict Diamond - Diamonds that originate from areas controlled by forces or factions opposed to legitimate and internationally recognized governments and are used to fund military action against those governments. Not considered ethical diamonds.
Crown - The top portion of a diamond, extending from the girdle to the table.
Crown Angle - The angle at which a diamond's bezel facets (or, on a round diamond, its star and upper girdle facets) intersect the girdle plane. This can greatly affect the diamond's brilliance.
Crystal - A mineral structure contained within the diamond.
Culet - The small facet at the bottom of a diamond.
Cushion Cut - A type of diamond cut that combines a square cut with rounded corners. It has been around for about 200 years, and until the early 20th century, it was the most popular diamond shape.
CVD (Chemical Vapor Deposition) - A method of growing diamonds in a lab by breaking down gases to obtain pure carbon, which is then used to form a diamond.
Depth - The height of a diamond from the culet to the table.
Depth Percentage - A ratio calculated by dividing the diamond's physical depth measurement by its diameter, which can affect the diamond's brilliance.
Diameter - The width of the diamond as measured through the girdle.
Diamond Gauge - An instrument used to measure a diamond’s length, width, and depth in millimeters.
Diamond Simulant - A stone that looks similar to a diamond but has different physical and chemical properties. Examples include cubic zirconia and moissanite.
Dispersion - The splitting of white light into spectral colors.
Emerald Cut - A type of diamond cut known for its rectangular facets and elongated shape.
Enamel - A glassy, decorative coating that can be applied to metal or pottery. It is often used in jewelry.
Eye-Clean - A term describing a diamond with no inclusions or blemishes visible to the naked eye.
Facet - The flat surface cut onto a diamond or gemstone.
Fancy Color - A term used to describe a diamond with a strong natural color, typically blue, pink, red, green, or yellow.
Fancy Shape - Any diamond shape other than round is often referred to as a "fancy shape". This includes princess, cushion, heart, pear, marquise, radiant, and others.
Feather - A type of inclusion in a diamond that looks like a small crack or fissure within the diamond.
Finish - The qualities imparted to a diamond by the skill of the diamond cutter. The term "finish" covers every aspect of a diamond's appearance that does not result from the diamond's inherent nature when it comes out of the ground.
Fire - The scattering of white light into all colors of the rainbow. This is seen as flashes of color in a polished diamond.
Flawless Diamond - A diamond grade that signifies there are no inclusions or blemishes visible under 10x magnification.
Florescence - A diamond's reaction to ultraviolet light. In some cases, fluorescence can make a diamond appear whiter or milky.
Fracture Filling - A treatment for diamonds where a glass-like substance is injected into the fractures to improve the gem's overall appearance.
GIA (Gemological Institute of America) - A nonprofit institute dedicated to research and education in the field of gemology.
Girdle: The outer edge of the diamond, where the crown (top) meets the pavilion (bottom).
Gold (White, Yellow, Rose) - Different colors of gold used in jewelry. White gold is alloyed with white metals, yellow gold is pure gold mixed with alloy metals, and rose gold is a mix of gold and copper alloy.
Grain - A unit of weight formerly used for pearls and diamonds, now largely displaced by the metric carat.
Halo Setting - A setting style that encircles a center gemstone in a collection of round pavé or micro-pavé diamonds (or other gemstones). These pavé stones flash with light and focus attention back on the center stone to enhance its brilliance.
Hardness - A measure of a material's resistance to being scratched. Diamond is the hardest known natural material on Earth.
Heart Cut - A type of diamond cut that is shaped like a heart.
High Relief - A term used to describe a gemstone setting where the stone is raised significantly above the band.
HPHT (High Pressure, High Temperature) - A method used to enhance the color of diamonds or create lab-grown diamonds. The treatment imitates the natural conditions under which diamonds form.
Ideal Cut - A term for a round diamond that has been cut to exact and precise angles and proportions to achieve maximum brilliance and fire.
GI (International Gemological Institute) - A laboratory for diamond grading.
Enter your text Inclusion - Internal or external characteristics that contribute to the overall clarity grade of a diamond. Inclusions can include internal features like crystals, clouds, or feathers, or external features like scratches and chips.
Industrial Grade - Diamonds that have significant inclusions or blemishes that make them unsuitable for use in jewelry. These diamonds are often used for industrial applications, such as cutting and grinding tools.
Invisible Setting - A setting technique in which gemstones are set to edge to edge with no metal separating them.
Jewelry Insurance - An insurance policy that provides coverage for your jewelry in case of damage, loss, or theft.
Karat (K) - The measurement unit used to describe gold's purity. 24K is pure gold, 18K is 75% gold, 14K is 58.3% gold, and 10K is 41.7% gold.
Kimberley Process - An international certification scheme that regulates trade in rough diamonds to prevent the flow of conflict diamonds.
Knife Edge - A type of ring setting where the band has a pointed edge. (Although it’s not actually sharp.)
Knot - An inclusion that extends to the surface after a diamond has been cut and polished.
Lab-Grown Diamond - A man-made diamond that is physically, optically, and chemically identical to a mined diamond.
Laser Inscription - The microscopically inscribed number on the girdle of a diamond that corresponds to a specific certificate of authenticity.
Loupe - A small, handheld magnifying glass used to see small details more closely. In diamond grading, a 10x magnification loupe is typically used.
Marquise Cut - A type of diamond cut that is elongated with pointed ends, also known as a navette cut.
Mine-to-Market - A term that refers to the journey a diamond takes from when it is mined to when it is sold as a piece of jewelry in the retail market.
Mounting - The part of the jewelry that holds a gemstone or diamond in place.
Needle - A long, thin, rod-like inclusion within a diamond.
Old European Cut - A style of diamond cutting popular from the 1890s to the 1930s, characterized by a round girdle, small table, open culet, and high crown.
Oiling/Resin Infusion - A type of clarity enhancement process where a colored oil or resin is used to make inclusions in a gemstone less visible.
Palladium - A precious metal used in jewelry making that is part of the platinum group of metals. It is lighter than platinum and similar in color to white gold.
Pavé Setting - A type of setting that involves setting small diamonds side by side with minimal visibility of the tiny metal beads or prongs holding the stones in place. A Micro Pavé setting involves setting smaller diamonds even closer together for an overall look of an unbroken sheet of diamonds.
Pavilion - The lower portion of a diamond, extending from the girdle to the culet.
Pear Cut - A type of diamond cut that combines a round cut's brilliance with a marquise cut's elongated design. The shape is round on one end and pointed at the other.
Pigeon's Blood - A term often used to describe the color of the highest-quality rubies. It refers to a vibrant, rich, slightly purplish red color.
Pinpoint - A very small inclusion within a diamond, often seen under 10x magnification.
Point - A unit of measurement used to describe the weight of diamonds. One point is equivalent to one-hundredth of a carat.
Polish - Refers to how smooth and defect-free the surface of a diamond has been left after the cutting process.
Princess Cut - A type of diamond cut that is traditionally square and features a high degree of brilliance. Learn more about princess cut diamonds.
Prong Setting - A type of setting in which a diamond is held in place by metal prongs.
Proportion - Refers to the relationship between the size, shape, and angle of each facet of a diamond. The consistency and balance of these can greatly affect the diamond's interaction with light and, thus, its brilliance and fire.
Refraction - The bending of light when it passes from one medium to another; in the case of a diamond, from air to diamond.
Rough Diamond - A diamond that has not yet been cut and polished.
Scintillation - The flashes of light you see when the diamond, light source, or observer moves. It includes both the internal and external reflections of light seen when a diamond is in motion.
Single Cut - A very small round diamond with only 16 or 17 facets, instead of the normal 57 or 58 facets of a full cut round brilliant.
Soldering - The process of joining two pieces of metal together with a filler metal at high temperatures.
Solitaire - A type of jewelry setting that features a single diamond or gemstone.
Symmetry - Refers to the exactness of the shape and arrangement of facets. This can include misaligning facets or facets that fail to point correctly to the girdle (known as out-of-point). Poor symmetry can hurt the diamond's brilliance by misdirecting light that enters the diamond.
Table - The largest facet of a diamond, located at the top.
Tension Setting - A type of setting in which the diamond is held in place by pressure rather than prongs.
Trillion Cut - A type of diamond cut that is triangular in shape.
VVS1 and VVS2 (Very, Very Slightly Included 1 and 2) - Clarity grades for diamonds with tiny inclusions that are difficult to see, even under 10x magnification. See our guides to learn more about diamond quality.
Weight Fraction - A term used in the gem industry, meaning that the weight stated is approximate.
White Diamond - A diamond with no hue in a gemological sense. The term is often misused to refer to colorless diamonds.
Yellow Diamond - A diamond with yellow as its primary color. It can range from pale to bright yellow. pure yellow diamond, often referred to as a "fancy colored diamond," holds greater value than a white diamond with yellowish tints, as the former is prized for its vibrant and rare coloration while the latter's yellow hue is considered an undesirable imperfection.