Abrasion:
Very small and tiny sketches on facet joints which fabricates white hairy lines instead of sharp crisp facet edges. Antique and other old or heavily used diamonds can have abrasions.

Adamantine:
This refers to the surface luster and shine of a diamond.

Adamas:
The word Diamond comes from this ancient Greek word ‘Adamas’, which means unconquerable.

Alluvial:
Stones those have been sourced from alluvial deposits in river beds or transported by water and deposited in seas and lakes. Many gems, including diamonds, are found in alluvial deposits and Alluvial diamonds are usually of gem quality.

American Cut:
Marcel Tolkowsky’s mathematically calculated ideal proportions and facet angles, to produce maximum brilliancy consistent with a high degree of fire in a round diamond brilliant, are known as American Cut or Ideal Cut.

Appraisal:
Appraisal is a written statement based on estimated retail replacement value of the polished diamonds. Appraisal is mainly used for insurance purposes and should be updated after every few years.

Artificial Diamond:
Artificial diamonds are produced by man in laboratory and mainly used in making artificial jewelry.

Canary:
A term used for diamonds with an intense yellow hue. The yellow color may appear with very slight greenish or slight orangey shade. Such diamonds are considered as Fancy and also called Fancy Yellow.

Carat:
The term Carat is used as a standard unit of measurement of the weight of diamonds and most other gemstones. The word comes from the carob beans which are known for its consistent weight and were used in ancient times to measure diamonds and other gemstones. One carat (ct.) equals 200 milligrams, or 0.2 grams (1/5 of a gram), or 1/142 of an ounce. There are 100 points in a carat. If all other factors are equal, the more a diamond weighs, the more valuable it will be. It is sometimes incorrectly spelled ‘Karat’, but Karat refers only to the fineness of pure gold and gold alloys.

Carbon:
Diamonds are composed of carbon entirely, or almost entirely.

Cavity:
A type of inclusion consisting of a large or deep opening in the diamond. It may be either internal or extending to the surface cause by cleavage or by a blow. Internal cavities may naturally contain gas, liquid, solid, a combination of two or three of these.

Certificate:
A statement or document issued and certified by a gemological laboratory which consists the genuineness of a diamond or other gemstone along with the quality and other characteristics.

Change of Color:
Sometimes diamond changes color or appears with a different color in different types of light. This is caused by selective absorption and/or transmission of the specific type of light to which the stone is exposed.

Channel Setting:
A setting style or method in channel form where no metal is displayed between stones.

Chip:
A curved break or absence of a tiny piece of a diamond, caused by normal wear and tear, or by cutting.

Clarity:
Clarity is one of the four value factors of a diamond which describes the absence or presence of flaws inside or on the surface of a diamond. Diamonds are graded on a scale from Flawless (no inclusions or blemishes visible under 10x magnification) to Included (eye visible inclusions or blemishes). If other factors are equal, flawless stones are most valuable.

Clarity Enhancement:
A process which is used to improve the apparent clarity of a diamond usually by filling fissures or fractures with a transparent substance like glass. Also known as ‘Fracture Filled’.

Clean:
A word used by some jewelers unofficially or informally which means flawless, or at least internal flawless.

Cleavage:
The tendency of crystalline minerals, such as diamond, to break in one or more definite directions, producing more or less smooth surfaces. A cleavage may be caused by inherent internal strain or by a sharp blow. Cleavage is one of the two methods used by diamond cutters to split rough diamond crystals in preparation for the cutting process. The other method is sawing.

Cloud:
A group of a number of extremely tiny white inclusions which gives a ‘cloudy’ or ‘milky’ appearance under 10x magnification. These clouds cannot be seen with the naked eye and generally does not significantly impact a diamond’s clarity grade.

Cluster:
This term is used for diamond ring or any other jewelry containing a number of diamonds. Cluster is also used for a number of kimberlite pipes occurring in close proximity.

Coated Diamond:
A diamond colored by a surface coating which masks the diamond’s true body color. Coating may be used extensively to entire pavilion or limited to one or two pavilion facets or a spot on the girdle.

Color:
Color is one of the four value factors of a diamond. Diamonds are ranked on a color scale from ‘D’ (colorless) to ‘Z’ (noticeable tint of color, typically yellow or brown). Diamonds with saturation greater than ‘Z’ color are considered Fancy Colored Diamonds such as blue, pink, purple, red etc. and are graded on a separate scale.

Color Grading:
A system of grading diamond colors based on their colorlessness (for other than fancy diamonds) or their spectral hue, depth of color or purity of color (for fancy color diamonds).

Colorless:
Colorless diamonds are white or transparent diamonds and promoted as the best, but only because other attractive colors are extremely rare.

Color Enhancement:
Color enhancement is the improvement process of a diamond’s color mainly by irradiation and HPHT (High Pressure, High Temperature). Sometimes color coating is also used to enhance the diamond’s color which is not considered as best enhancement way.

Commercial:
This term is used for medium to low quality diamonds and opposite to fine gem quality.

Created:
A description of synthetic diamonds opposite to natural ones.

Critical Angle:
Critical angle is the largest angle measured from the normal angle from which light can escape, is an optically dense substance, and the smallest angle to the normal angle at which light is totally reflected within the dense substance.

Crown:
The upper portion of a cut diamond above the girdle which consists of a large flat area on top known as table, and several facets below it.

Crown Angle:
The angle between the girdle and diamond’s bezel / concentric facets is known as crown angle. This gentle slope of the facets that surround the table helps to create the dispersion or fire in a diamond. White light enters from the crown angles and brakes up into its spectral hues which ultimately enhance the brilliance of a diamond.

Crown Height:
The height or depth of the crown of a diamond, above the girdle.

Crystal:
A diamond is a crystal which is formed entirely or almost entirely by carbon. Sometimes crystal is also considered as a type of inclusion which is a mineral deposit trapped inside the diamond.

Culet:
The smallest facet at the bottom of most round or brilliant cut diamonds is known as culet. Its purpose is to protect the tip of the pavilion from being chipped or damaged. Most modern shapes have either no culet at all, or a small or very small culet.

Cushion:
A shape of diamond, which ranges from square to rectangular and it has rounded corners and larger facets to increase its brilliance. Cushion Cut diamonds are also known as “pillow cut” diamonds.

Cut:
Cut is one of the major value factors of a diamond. The cut, also called make, of a diamond refers to the proportions and finish given to the polished diamond by the diamond cutter. Proportions are the size and angle relationships between the facets and different parts of the diamond. It is the only man-made contribution to a diamond’s beauty and value.

Cutter:
The person who cuts and polishes rough diamonds and convert them into finished diamonds.

Cutting:
The process of cutting, grinding or polishing rough diamonds and convert them into finished diamonds.

CZ:
CZ denotes cubic zirconium, a widely used simulant, an imitation for a natural diamond. Although CZ is easily detectable by it’s 80% higher weight than a diamond of the same proportions or by thermal conductivity testing.

Deep:
This usually means a diamond which has been cut too deep. This deep cut maximizes weight but sacrifices brilliance.

Depth:
The height of a diamond from the table to the culet which is measured in millimeters.

Depth Perception:
The depth percentage, which expresses how deep the diamond is in comparison to how wide it is. In other words, the depth of the diamond is divided by the average width. This depth percentage of a diamond is important to its brilliance and value. The pavilion should be deep enough to allow light to bounce around inside the diamond and be reflecting out to the eye at the proper angle.

Diameter:
The width of the diamond, as measured across the widest part of the girdle.

Diamond:
The word “diamond” comes from the Greek word “Adamas”, meaning “Unconquerable”. Diamond is composed of carbon that crystallizes in the “cubic,” or “isometric,” crystal system. It is the hardest known substance in the world (10 on Mohs’ scale). The Diamond is uniquely resistant to damage by heat or scratching, and can be cut or polished only by another diamond. It occurs in colors ranging from colorless to yellow, brown, orange, green, blue, and violet.

Diamond Cutter:
The person who cuts and polishes rough diamonds and convert them into finished diamonds.

Diamond Cutting:
The process of cutting, grinding or polishing rough diamonds and convert them into finished diamonds.

Diamond Gauge:
An instrument that is used to measure a diamond’s length, width and depth in millimeters.

Diamond Saw:
A saw used for dividing or separating diamonds.

Direction:
Hardness is directional in diamonds and it is important for cutting. The optimal direction of cutting and polishing depends on the optical axes of diamonds.

Dispersion:
Dispersion is the ability of a diamond or other gemstone, to separate white light into the colors of the spectrum. Diamond has the highest dispersion (.044) of any natural, colorless gem.

Drill, Drilling:
Now laser is used to drill a diamond neatly for removing inclusions as well as drilling could also be done to create a diamond bead.

Durability:
Durability describes a diamond’s resistance power against scratches and cracks due to wear. The durability of a diamond depends on its hardness, toughness and stability.

Dust:
Very tiny rough diamonds and generally used as abrasives. It is also known as diamond powder.

Gauge:
Any device or instrument which is used to calculate the weight of diamonds, by measuring or estimating physical dimensions like diameter, depth, length.

Gemologist:
A person with expertise in gemology is known as gemologist. There are many recognized courses available from various Gemological Institutes which offer study in gem identification, grading and pricing, as well as diamond grading and appraising.

Gemological Institute of America (GIA):
Gemological Institute of America (GIA) was founded as non-profit organization in 1931 by Roger Shipley. GIA maintains the highest standards for grading diamonds and other precious gems and it has one of the world’s most-respected and well-regarded gemological laboratories. GIA has developed and standardize the diamond grading system that is used by nearly all other gem labs.

Gemstone:
A gemstone is a mineral or rock, which can be used in jewelry after cutting or faceting and polishing. Gemstones are diverse in their beauty and many gems are available in a stunning variety of colors. Most gemstones have little beauty in the rough state. They may look like ordinary rocks or pebbles. After a skilled cutting and polishing of a gem, full color and luster can be seen.

Girdle:
Girdle is the widest part or outer edge of the diamond and the dividing line between the crown and pavilion. The girdle can be rough (matt), faceted, polished or unpolished but a polished or faceted girdle doesn’t improve a diamond’s grade. Most labs grade a girdle’s thickness, not its appearance and the descriptions of girdle thickness range as follows: extremely thin; thin; medium; slightly thick; thick; extremely thick.

Girdle Facet:
The 32 triangular facets that adjacent to the girdle on a brilliant cut or other diamond and split into 16 upper (crown) girdle facets, and 16 lower (pavilion) girdle facets. Sometimes facets are placed directly on the girdle, in which case the diamond is usually said to have a ‘faceted girdle’.

Girdle Thickness:
It is the measurement describing the percentage of the diamond’s average girdle diameter. The girdle thickness ranges as follows: extremely thin; thin; medium; slightly thick; thick; extremely thick.

Gridling:
Girdling is the process of giving a circular shape to a diamond. In this process, a diamond is held in a lathe, or in a cutting machine, and cut or shaped by another diamond, called a sharp.

Gold:
Gold is a yellow precious metal used in most jewelry with various alloys.

Grade:
A recognized measure of an aspect of diamond’s quality, mainly clarity and color.

Grading:
The process of evaluating a diamond, and allocating grades to it.

Grading Report:
A grading report or certificate is a statement, issued by an independent Gemological Laboratory, that at the time of evaluation, the Diamond in question has been examined, measured, and scrutinized by experienced Diamond Graders, using various gemological instruments, and determined to contain the characteristics as stated in the Report or Certificate. The grading report should accurately describe the proportions, weight, color, clarity, symmetry, polish and possible fluorescence seen in the diamond.

Grain:
Diamond crystals have different strength bonds in different directions and these directions are known as grain.

Graining:
Usually graining refers to internal irregular crystal growth which may appear milky like faint lines or streaks.

Gypsy Setting:
The gypsy setting is a recessed setting in which the stone is sunk into the metal and there are often engraved designs around the stone especially in star patterns. The gypsy setting is also known as the ‘star setting’.

Hardness:
The hardness of a diamond refers it’s resistance to scratching on a smooth surface. Diamond is the hardest known substance on Earth and it is graded 10 on Mohs’ scale of hardness. Hardness is directional in most gemstones.

Head:
Head refers part of the setting that holds the center stone or solitaire in place.

Heart Cut:
The Heart shaped diamond is a fancy cut diamond and essentially a pear-shaped with a cleft at the top and which typically contains 59 facets. Due to the complexity of the shape, skilled cutting is necessary to maintain the diamond’s brilliance. Generally people prefer a heart shape diamond for sentimental purposes. This shape is mostly used in pendants, but also suitable for most jewelry items.

Heat Treatment:
Heat treatment is the process in which heat is offered to a gemstone for the purpose of improving its color.

Hue:
Hue is an aspect of color such as pink, yellow, blue, green, etc. It is a primary factor in viewing and grading fancy colored diamonds.

Imperfect:
The diamond imperfection grade at the low end of the ‘flawless-to-imperfect’ scale. An imperfect diamond contains any external blemish or internal inclusion or flaw that are visible to the unaided eye or that have a serious effect on the stone’s durability.

Included Crystal:
A diamond which contains a mineral crystal is known as included crystal.

Inclusion:
An internal imperfection or characteristic which reduces the clarity or brilliance of a diamond. Common diamond inclusions are feathers, crystals, fractures, needles, graining, pinpoints and cavities.

Industrial Diamonds:
Low grade or very small diamonds which are not perfect for jewelry use and are generally used in various industrial applications.

Internal Graining:
A diamond which contains internal irregular crystal growth is known as internal graining. It may appear milky like faint lines or streaks.

Internally Flawless (IF):
A clarity grade which refers no inclusions and only insignificant surface blemishes.

Irradiated Diamond:
A diamond which has been exposed to radiation usually to improve its color.

Karat, Karat Weight:
Karat is the American spelling of carat which is now only used for gold or gold alloys weight whereas English spelling carat is used in respect of weight of diamonds or other gemstones. Karat is always based on pure 24 karat gold and if a jewelry item contains 18 karat gold that means it has eighteen parts pure gold and six parts other metal alloys.

Kimberlite Rock:
The yellow or blue rock which forms diamond pipes, and in which most diamond is found.

Knot:
An included diamond crystal which reaches to the surface of a polished diamond. This knot is difficult to cut or polish because of twinning, negative crystal growth, or similar feature.

Main Facets:
The large crown and pavilion facets of a brilliant-cut diamond whereas on step-cut stone, the center row of facets on the pavilion.

Make:
Make is a trade term refers to the proportions, symmetry and polish of a diamond or a gemstone.

Marquise Cut:
The Marquise Cut is a traditional shape having elongated ends at both edges. The pointed ends make this shape the most fragile and the most expensive of brilliant style cuts. It has a total of 56 facets and construction of facet requires a lot of experience and delicacy of the sharp points demands utmost precaution. Now-a-days this shape is very popular for engagement rings.

Melee:
This term is used to describe small brilliant-cut diamonds under .20 carat. Generally, these small diamonds or gemstones are used to embellish mountings, setting or larger stones.

Mine:
A place where diamonds are extracted from the ground, by using various methods of mining like open cast, deep pit etc.

Mineral:
Mineral is a naturally occurring, inorganic element of the Earth with a consistent atomic structure and chemical composition.

Modern Brilliant Cut:
It is a round brilliant cut unless otherwise stated normally with 58 facets including the culet and polished using relatively modern theory. This shape is considered as ideal for a diamond because it maximizes a stone’s sparkle and brilliance.

Modified Brilliant Cut:
A diamond cut in a shape or style other than round brilliant cut, such as oval, pear, marquise, heart, princess, radiant, or baguette.

Mohs Scale:
It is a ten point scale to find mineral hardness which is devised by Friedrich Mohs, a German mineralogist, in the 19th century. The diamond is the hardest of all known natural substances and it scores 10 on Mohs Scale.

Moissanite:
Transparent silicon carbide, which is a rare crystal in nature, marketed as a diamond stimulant. It is named after Henri Moissan, famous French scientist. Its double refraction is one of the few differences with a diamond whereas thermal conductivity is almost equal.

Mounting:
The process of making a ring or other piece of jewelry into which gemstones will be set.

Natural:
A small portion of the original surface of a rough diamond left by the cutter when polishing and faceting a diamond which is frequently on or near the girdle. This is generally the sign of a cutter attempting to maximize the weight retention of the rough diamond. Usually naturals do not affect the clarity grade and in most cases, they are undetectable to the naked eye.

Needle:
A long, thin and sharp crystal inclusion which looks like a tiny rod.

Nick:
A minor chip out of the surface of a diamond, usually found near or on the girdle of the stone.

Off Make:
A poorly proportioned Diamond, particularly with poor symmetry.

Old European Cut:
The earliest known form of brilliant cut diamond with a very small table, a heavy crown, and usually great overall depth. This is also known as old mine cut.

Opaque:
Opaque refers to the transparency of a diamond. Generally opaque material does not transmit light.

Oval Cut:
The Oval Cut is a beautiful Fancy shape which offers great brilliance and fire through its 56 facets. This is an elongated version of round cut, provides the same brightness which comes from a round brilliant shaped diamond.

Parcel:
Parcel is a packed paper envelop for diamonds which is purchased by buyer without selection of containing diamonds. Although sometimes buyer is permitted to reject a small number of diamond.

Paste:
Powder of very small diamonds in paste form, which is made with oil or any other binder and used as an abrasive for cutting and polishing any material including other diamonds.

Pave:
An attractive style of jewelry setting in which numerous small diamonds are mounted as close together as possible to create a sparkly diamond shell. This setting style covers the whole piece of jewelry with diamond crust and conceals the metal under it.

Pavilion:
Pavilion is the lower part of a diamond, below the girdle.

Pavilion Angle:
This is the angle between the main pavilion facets and the girdle. In a diamond, this is the most important dimension and ideal pavilion angle should be around 40.75° to 41°.

Pavilion Main Facet:
The eight facets found on the pavilion of a round brilliant diamond.

Pear Cut:
The Pear Cut is a fancy shape diamond that looks like a teardrop due to its single point and rounded end with 56 to 58 facets. This shape is popular for its uniqueness and brilliance.

Phosphor-escence:
A diamond, which is exposed to daylight, ultra-violet or other light, continues to glow after the light source has been removed.

Pick:
The term pick is used when seller permits buyer to select one or more diamonds from a parcel.

Pink Diamond:
Pink is one of the rarest and most desirable fancy colors for a diamond. Any diamond with pale reddish, purplish-red and purplish hue is known as pink diamond.

Pinpoint:
Tiny or very small inclusions, of pinpoint size, internal to a diamond. Whereas a cluster of pinpoints can form a cloud.

Pipe:
This term is used for vertical, columnar rocks that are originated due to lava flow and after that cooled and solidified in the neck of a volcano. When these rock masses consist of kimberlite, they often contain diamonds.

Pit:
A tiny opening or surface mark on a diamond which often looks like a white dot.

Plotting Diagram:
A graphical representation or a diagram in a diamond certificate that illustrates the facets of a diamond as well as the approximate locations and types of internal and external characteristics. These characteristics can be spotted as internal and external by the different colors generally red and green.

Point:
A unit of measurement which is used to describe the weight of diamonds where one point is equivalent to one-hundredth of a carat. For example, a 1/2 carat diamond weighs 50 points.

Polish:
Polish is considered as smoothness of the surface of a fashioned diamond in which optical reflection is maximized. Generally a polished diamond does not show visible wheel marks or burn marks under 10X magnification. Polish is an indicator of the quality of diamond’s cut which is graded as Ideal, Excellent, Very Good, Good, Fair or Poor.

Polishing:
The process of polish which converts a diamond’s rough or irregular surface to a smooth surface by using various methods.

Polished Girdle:
A girdle that is polished or lapped to yield a lustrous and highly reflective surface.

Polish Lines:
Polish lines refer tiny or faint surface lines which are visible due to imperfect polishing or irregularities in crystal structure.

Polish Mark:
A burn mark or surface clouding on a diamond caused by excessive heat while grinding or polishing.

Price:
Price of a diamond is extremely variable and based on all aspects of quality.

Princess Cut:
The princess cut is a fancy shape diamond which has pointed corners and square in shape. The ideal princess cut will have length to width ratio is as close to 1.00:1.00 as possible, as princess cut diamonds can range from this perfect square through to almost rectangular. This cut is the most popular non-round diamond cut.

Prong Setting:
Prong setting is the most frequently used method of setting diamonds into jewelry. This setting usually consists of four or six small metal tips or claws to hold the diamond tightly. This setting allows maximum amount of light to enter in a diamond from all angles and because of this, stone appears more brilliant and larger than its actual size.

Proportion:
The consideration of each part of a diamond in relation to all other parts. Proportion is an important quality element which evaluates the overall shape of a diamond.

Purity:
Purity is also known as clarity which describes the absence or presence of flaws inside or on the surface of a diamond. Diamonds are graded on a scale from Flawless (no inclusions or blemishes visible under 10x magnification) to Included (eye visible inclusions or blemishes). If other factors are equal, flawless stones are most valuable.

Saturation:
A color’s position in a diamond on a neutral to vivid scale.

Scintillation:
This term refers to the display of sparkle or reflection from the polished facets of a diamond visible when the observer is in motion.

Scratch:
Scratch is a narrow, shallow, elongated nick on the surface of a diamond which usually appears as faint white lines, curved or straight, under magnification.

Secondary Deposit:
Minerals and/or gemstones that have been separated from their original host rock, usually due to effects of weather, and deposited elsewhere. An alluvial deposit is an example of a secondary deposit.

Semi Precious, Semi Precious Stone:
Stones those are valued for their beauty and not covered under any one of the four ‘Precious Stones’, Diamond, Emerald, Ruby or Sapphire, are known as semi precious stones. Semi precious stones are available in all price ranges from low priced to high priced. Semi precious stones are Alexandrite, Amethyst, Aquamarine, Citrine, Garnet, Iolite, Onyx, Opal, Pearl, Peridot, Tanzanite, Topaz, Tourmaline etc.

Semi-mount:
A style of jewelry setting that has the side stones already mounted, but which contains an empty set of prongs which are intended to mount a diamond center stone as per the customer’s choice.

Setter:
Setter is the person who puts diamonds or other gems into jewelry mounts.

Setting:
Setting is the process of fixing a diamond or other gem into a mount to create a piece of jewelry.

Shape:
A Diamond Cut by Shape describes the outline of the stone and pattern of the facet arrangement. Diamonds are available in various shapes like Modern Round Brilliant, Emerald, Princess, Heart, Oval, Pear etc. Round brilliant is the most popular shape for all jewelry items. All other non-round shapes are called fancy shapes.

Sieve:
A tool for sorting rough or polished diamonds by size. Diamond sieve sets have interchangeable sieve plates each drilled with different sizes holes.

Silver:
Silver has been known and used for thousands of years and it is considered as one of the three precious metals along with gold and platinum. Pure silver is very soft metal with its lustrous white color. Silver is used as jewelry metal well before the development of white gold alloys, and before platinum could be isolated.

Simulant, Simulated Stones:
Simulated stones can be anything that resembles a natural gemstone but does not have the same physical characteristics or chemical composition. These items are also known as imitation stones and usually much less expensive than the natural forms. Simulated stones are often made of glass or plastic and most can be detected easily by a jeweler.

Single Cut:
A very small round diamond with only 17 or 18 facets, instead of the normal 57 or 58 facets of a full cut round brilliant. These facets include 8 bezel, 8 pavilions, a table and sometimes a culet facet.

Slight Inclusions, SI, SI1, SI2:
Slightly Inclusion is clarity grade that refers slight inclusions in a diamond which are easily visible under 10X magnifications. It is graded as SI1 and SI2.

Solitaire:
A ring or any other piece of jewelry containing a single diamond or other gem. This style is very popular in rings.

Sort, Sorting:
Usually this term is used to classify rough diamonds into groups depending on their size, color, surrounding material where as in case of polished diamonds it is used classify into grades depending on size, color, clarity.

Spread Stone:
A Diamond which has been cut with a large table and a thin crown, to retain greater weight. In other words, a diamond which is cut too shallow.

Star Facet:
The eight triangular facets that surround the table facet of a round, brilliant-cut diamond. It is named star facets because they from an eight pointed star when viewed from above.

Step Cut:
Step cut is a style of faceting arrangements which is named because of its broad, flat planes that resemble stair steps. In this style of arrangement, there are three concentric rows of facets arranged around the table and, on the pavilion, there are three concentric rows arranged around the culet.

Stone:
A general word for any gemstone including diamond.

Surface Graining:
Surface graining is an indication of structural irregularity in a diamond. Usually parallel lines are visible on the surface or facet edges which look similar to grain in wood. These grain lines reflect due to imperfect polishing.

Symmetry:
Symmetry is an important aspect of the diamond cutting process which refers to the balance of the outline shape and alignment of the facets. It is graded as Ideal, Excellent, Very Good, Good, Fair or Poor.

Synthetic:
A synthetic diamond shares a natural stone’s physical, chemical and optical qualities, but it is created in a laboratory. Some modern synthetic diamonds look more natural and are more difficult to identify, but an experienced jeweler or gemologist can usually detect them.

Table:
Table is the largest and flat facet which is placed on top of a diamond. Most of the light enters and exits from this part of a diamond.

Table Percentage:
The table percentage is a comparison of the diameter of the table facet to the diameter of the entire diamond.

Tension Setting:
A method of setting diamonds and other gems using only the springiness of the mount to hold the stone firm. Although it look quite spectacular but very unsafe and it should be avoided.

Tone:
An attribute of color which determines its lightness or darkness of shading and important in grading fancy colored diamonds.

Transparent, Transparency:
Ideally, a diamond should be completely transparent and any opacity is undesirable.

Treated Diamond, Treatment:
Treated diamonds are those which have been processed in some way to enhance their color or clarity. A number of treatment techniques are used to improve the color and appearance of natural and synthetic diamonds. Heat treatment is the oldest method whereas other techniques include bleaching, dying, laser drilling, fracture filling, high pressure high temperature (HPHT), annealing, irradiation, and surface coloration.

Trigon:
Trigon refers to very small triangular marks usually on surfaces of rough and polished diamonds, due to twinning and other crystal growth factors.

Trilliant Cut, Trillion Cut:
The Trilliant Cut is a triangular fancy shaped diamond which is also known as Trillion Cut. This shape of diamond looks unusual and displays a very sharp brilliance or fire. It may either have pointed corners or more rounded corners.

Twinning:
Twinning refers to two or more mineral crystals that have grown together in a symmetrical nature and crystal growth direction of one crystal has changed or a negative crystal growth has taken place.

Ultrasonic Cleaner:
Ultrasonic Cleaner is a tool, generally used by jewelers, to clean jewelry effectively. The ultrasonic vibrations help to free most types of dirt, grime, and oils from these jewelry items. Some ultrasonic cleaners come with a heating unit also.

Ultraviolet light:
Ultraviolet light consist short wavelengths in comparison of visible light’s wavelengths and due to this it is invisible to naked eye. Ultraviolet light is in between visible light and X-rays.

Upper Girdle Facet:
Upper Girdle Facet is any of the sixteen facets on the crown, adjoining the girdle of a diamond.

Vivid:
The term vivid is used for color grading of fancy colored diamonds to denote the most intensely colored stones.

Very Slight Inclusions, VS, VS1, VS2:
It is a clarity grade that refers minor or slight inclusions in a diamond which are difficult to see under 10X magnifications. It is graded as VS1 and VS2.

Very Very Slight Inclusions, VVS, VVS1, VVS2:
It is a clarity grade that refers tiny or very slight inclusions in a diamond which are extremely difficult to find, even under 10X magnifications. It is graded as VVS1 and VVS2.

White Diamond:
White diamonds are transparent or colorless and promoted as the best, but only because other attractive colors are extremely rare.

Wisp:
Wisp refers to a type of inclusion which occurs due to twinning or in other words it is an irregularity in the crystal growth.