Ratna Jyoti:: Glossary Education
An educational institution for gemological studies that enjoys international acceptance and trains gemologists from all over the world. Certification
Alloy :-The mixture of two or more metals to improve durability or tensile strength. Many alloys are used in jewellery, such as rose gold which is an alloy of yellow gold and copper.
Appraisal:- A documented estimate by experts, of the approximate retail value of an item. Appraisals are most often used for insurance purposes to estimate replacement value.
Asscher-Cut Diamond:- A diamond cut named after its inventor, Joseph Asscher, this is a square cut diamond with 72 facets.
Baguette: A rectangular-shaped stone with rows of step-like facets. Baguettes in long, thin cut rectangles are often used as enhancements to a solitaire, or on a watch bezel
Band (Wedding):- A plain ring which fits like a band around the ring finger usually used as a symbol of marriage. This can occasionally be set with small diamonds.
Bangle:- A round bracelet usually worn around the wrist. This is firm and solid, unlike bracelets that are pliant or can be bent.
Bar Channel Setting:- Similar to channel setting, it is a circular band of diamonds or gemstones wherein a thin metal bar between the stones hold each stone in place.
Bezel Setting:- In a bezel setting, a metal rim holds the stone and surrounds the gem above the girdle.
Bezel settings are considered safe and secure mounts.
Blemish:- A flaw in clarity that can be seen on the surface of a diamond. Though some blemishes are inherent to the original rough diamond, most are the result of the conditions in which the diamond was kept and handled after being mined.
Brightness:- Light reflection seen in the top view of a diamond.
Brilliance:- The sparkle of a stone that is a result of the total internal reflection of light from the top surface of the diamond. Brilliance is created primarily when light enters through the table, or flat top of the diamond, bounces about on the pavilion facets, and is then reflected back out through the table, where it is most visible to your eye.
Brilliant Cut:- Brilliant cuts are most popular because they reflect the maximum light from within the stone and are often considered to make a diamond sparkle more brightly than all cuts. A round brilliant-cut diamond has 58 facets. Other brilliant cuts include the heart, oval, marquise and pear shaped cuts.
Carbon Spots:- Certain inclusions in a diamond such as crystals that have a dark appearance, rather than a white or transparent appearance, when viewed under a microscope. In most cases, these dark inclusions are not visible to the naked eye, and do not affect the brilliance of the diamond.
Carat:- The unit of measure of weight of diamonds and gemstones. One carat is equivalent to 200 milligrams. One carat can also be divided into 100 points. A .75-carat stone is the same as a 75-point or 3/4-carat stone. The word ‘carat’ comes from the carob bean, whose consistent weight was used in ancient times to measure gemstones.
Center Stone:- The focal gemstone in any setting with many different stones.
Certification :-There are many recognized gemological laboratories that grade stones for a fee. The one with the widest acceptance which is known all over the world is the RJL.
Channel Setting:- This setting is used most frequently for wedding and anniversary bands, with the stones set right next to one another with no metal bars separating them.
Chip:- A tiny missing piece of the diamond, caused by normal wear and tear, or by cutting.
Clarity:- A diamond, being a natural stone often has natural imperfections, commonly referred to as inclusions, which actually contribute to its ‘signature’ or identifying characteristics. Inclusions are found within the diamond, and can be white, black, colourless, or even red or green. Most are undetectable by the human eye, and can only be seen with 10X magnification. Inclusions are ranked on a scale of perfection called clarity.
Clasp:-The metal fitting that allows a piece of jewellery to be held fast. Clasps come in different styles and differ for items like necklaces and bracelets.
Claw Setting:- A type of prong setting where the metal pieces that hold the stone resemble claws. These suspend a stone in an open mounting, allowing more light to enter from the sides of the ring to promote maximum brilliance.
Cloud:- Clouds also referred to as Pinpoint Inclusions: Pinpoints are extremely tiny crystals that occur mostly in clusters within diamonds. Larger clusters of minute pinpoints can create a hazy area which looks like a ‘cloud’, lowering the clarity of the diamond. Usually clouds do not impact a diamonds clarity grade.
Colour:- The colour of a gemstone when exposed to light. Diamonds are usually colourless, reflecting most of the light that enters them as pure white light.
Coloured Diamonds Fancy colours refer to diamonds with hues like pink, blue, green, yellow, and very rarely, red. Fancy colours are not included in the colour scale and are considered extremely rare.
Crown:- This is the upper part or the top of a diamond, which lies above the girdle.
Crown Angle:- The angle at which a diamonds bezel facets (or, on emerald cuts, the row of concentric facets) intersect the girdle plane. This gentle slope of the facets that surround the table is what helps to create the dispersion, or fire, in a diamond. White light entering at the different angles in broken up into its spectral hues, creating a beautiful play of colour inside the diamond. The crown angle also helps to enhance the brilliance of a diamond.
Crystal:- A crystal is an inclusion characterized by a mineral deposit trapped inside the diamond.
Culet:- A facet or point at the bottom of the pavillion of a diamond. Diamond Anatomy.
Cushion-Cut Diamond:- A mixed-cut diamond shaped like a square pillow.
Cut:- This refers both to the proportions and the finish of a polished diamond. As one of the four ‘C’s of diamond value, it is the only man-made contribution to a diamonds beauty and value. Cut refers to the angles and proportions a skilled craftsman creates in transforming a rough diamond into a polished gem. Cutting is based on scientific formulae and has been developed into an art by certain communities, craftsmen and designers.
Cutting style:- Cutting styles are different from diamond shapes. There are three basic types of cutting styles, Step-cut, Brilliant-cut and Mixed-cut.
Depth:- The height of a diamond from the culet to the table. The depth is measured in millimeters.
Depth Percentage:- There are two different measurements of the diamonds depth mentioned on a diamond grading report - the actual depth in millimeters (under measurements at the top of the report) and the depth percentage, which expresses the proportion of the depth to the width.
Diamond:- A diamond is the hardest known natural substance. A crystal made up of 99.95% pure carbon atoms, it is crystallized carbon. Diamonds are mined in their rough form and then, cut and polished to reveal their brilliance.
Diamond cutting The method by which a crystal made up of 99.95% pure carbon atoms, that is, a rough diamond mined from the earth, is shaped into a finished, faceted stone.
Diamond gauge:- An instrument that is used to measure a diamonds length, width and depth in millimeters.
Diamond grading report:- The report given by a recognized gemological laboratory that gives the grade, quality and characteristics of your diamond for a fee.
Dispersion:- Popularly referred to as the ‘Fire’ of the diamond, this is the dispersion of light after it enters a diamond, reflects off the facets and the angles cut into the stone.
Drop Earrings:- Earrings that have one part attached to the ear, and another part hanging suspended from this portion to resemble a ‘drop’
Emerald-Cut :-A rectangular or square-shaped cut-cornered diamond. A step cut, it is favoured for diamonds and emeralds, when the principal purpose is to enhance colour rather than brilliance. It is also sometimes used to emphasize the absence of colour in diamonds.
Engrave:- Inscribed letters or designs that are etched into the metal surface of jewellery.
Enhancements:- Methods used to enhance the appearance of diamonds in laboratories, by removing inclusions
Eye-Clean:- A term used in the jewellery industry to describe a diamond with no blemishes or inclusions that are visible to the naked eye.
Facet:- Any flat polished surface of a diamond or gemstone which allows light to both enter a diamond and reflect off its surface at different angles, creating the wonderful play of colour and light for which diamonds are famous. The placement, angle and shape of different facets are carefully planned and executed to show the stones inherent beauty, fire, colour, and brilliance to the fullest advantage. Diamond Anatomy
Fancy-Colored Diamond:- Diamonds found in their natural state in any colour except the pure, colourless diamonds with yellow or brown shades in the colour grading scale that are normally used in jewellery. Fancy colours can include canary yellow, and the rarest shade of all – a red diamond.
Fancy-Shaped Diamond:- Diamonds that have been cut into any shape other than round brilliant. While there are eight known fancy shapes such as Marquise, Pear, Princess etc. designers come up with new fancy shapes from time to time.
Feather:- These are small fractures in a diamond, caused by the stress the diamond suffered in its natural state
underground. With normal wear and care, most feathers pose no risk to the diamonds stability.
Fire:- This is often a term used to describe the ‘dispersion’ in a diamond. It is the variety and intensity of rainbow colours seen when light is reflected from a diamond.
Fluorescence:- This is the tint visible when a diamond is exposed to ultraviolet light, which may be whitish, yellowish or bluish. The untrained eye can rarely see the effects of fluorescence. Diamond grading reports often state whether a diamond has fluorescent properties. Fluorescence is not considered a grading factor, only a characteristic of that particular diamond.
Fracture:- Imperfections (small cracks or fissures) on the surface of a gemstone. Fractures show up as white areas inside the diamond because light does not pass through them as it does the remaining portion of the stone.
Fracture filling:- A process that injects a substance into a diamond to hide inclusions.
Girdle :-The outer edge, or outline, of the diamonds shape. The outer edge of a cut stone, this is the dividing line between the crown and the pavilion. Sometimes the girdle is polished and sometimes it is unpolished. Ideally, the width of the girdle should be even and proportional to the cut of the stone.
Girdle Thickness:- This is the thickness of the outer edge of a diamond which forms a band around the circumference of the stone
Gold:- The precious yellow metal with a universal acceptance as a mount for jewellery.
Grading Report, Grading Certificate:- A grading report is issued by an independent laboratory, not by the jeweler selling the diamond, and should accurately describe the proportions, weight, color, clarity, symmetry, polish and possible fluorescence in the evaluated diamond. Many experts feel that the GIA and AGS labs are more consistent and stringent in their grading than other labs.
Graining:- Internal indications of irregular diamond crystal growth. Internal graining generally appears milky, or like faint lines or streaks, and may be coloured or reflective
Hinged Hoop Earring:- A hoop earring that has a hinge as a part of its design.
Hinged snap backing:- A fitting to hold jewellery in place where a hook fits into a corresponding loop.
Hue:- Hues are pure, spectral (prismatic) colours of gems. Hues include gradations and mixtures of red, orange, yellow, green, blue, violet and purple.
Illusion setting:- The invisible setting technique was developed in France more than two centuries ago. Grooves in each stones girdle slip into a metal framework below the surface, but the metal cannot be seen, so gemstones sit side-by-side where they create the appearance of a solid surface of stones.
Inclusion:- These are internal imperfections within most diamonds and influence a diamondsclarity rating. Most of the diamonds contain inclusions, which are created during the Diamonds formation in the earth.
Karat:- The measurement of the purity of gold. Precious Metals
Laser Drill Hole:- A tiny tube created in a diamond by laser drilling, which is often done to treat or enhance diamonds. Laser Inscription:- An inscription created within the diamond by the process of laser drilling.
Length-to-Width Ratio:- A comparison of the length and width of the girdle on diamonds. The ratio is found by dividing the length of the diamond by the width.
Lobster Claw Clasp:- A means of fastening jewellery that is shaped to resemble a lobster claw.
Loupe:- Any small magnifying glass mounted for hand use, to hold up to the eye socket or attach to a pair of glasses.
Marquise-Cut Diamond:- A double-pointed, boat-shaped long and thin stone with curved sides coming to a point on either end. Part of the brilliant-cut family; ideally, the marquise cut has 58 facets.
Matching:- The quality of stones to be very similar in colour and clarity. Stones are matched to be combined in settings with multiple diamonds
Millimeter: : A metric unit of measurement of size or distance
Mixed cut:- This cut has both step-cut and brilliant-cut facets. Mixed cuts combine the beauty of the emerald cut with the sparkle of the brilliant cut.
Needle:- A long, thin included crystal which looks
like a tiny rod
Opaque:- A substance that does not reflect light back outside. It is the opposite of transparent
Pave:- A type of setting where a number of small stones are set together to resemble a cobble-stoned street. It literally means ‘paved with diamonds’.
Pavilion Angle:- The angle measured between the main facet of the lower portion of the diamond and the girdle. Diamond Anatomy
Polish:- Indicates the care taken by the cutter in shaping and faceting the rough stone into a finished and polished diamond.
Precious Metals:- Gold, Silver, Platinum and the other members of the Platinum group. (Precious Metals)
Prong Setting:- The metal tip or bead that actually touches the stone and holds it into place. This setting usually consists of four or six claws that cradle the stone. As it allows the maximum amount of light to enter a stone from all angles .
Proportion:- The proportions of a diamond are very important to allow the maximum amount of light to be reflected off and out of a stone. Proportion is the relationship between the angles of the facets of the crown and pavilion.
Rhodium:- Rhodium is a hard silvery white and durable metal that has a high reflectance. Rhodium metal does not normally form an oxide, even when heated. Rhodium has both a higher melting point and lower density than platinum. It is not attacked by acids: it is completely insoluble in nitric acid
Ring Setting:- Collective term for the shank and the head of a ring which contains the center stone.
Ring Size:- A measurement determined by two factors: the diameter of the finger on which the ring will be worn, and the knuckle which the ring must slip over comfortably.
Safety Clasp:- A secure means of fastening jewellery that prevents the clasp from opening through casual handling. This usually has a double hinge to fasten the clasp.
Saturation:- A diamond colours position on a colour scale, measured from a neutral rating to vivid.
Scintillation---- The sparkling flashes that leap out of the gem when light reflects from a diamond.
Screw Back--- A means of fastening earrings wherein the earrings are held in place by means of a screw with its corresponding .
Setting ----The metal mount for a piece of jewellery
Setting Type---- The setting / mount for a jewellery comes in various kinds like Prong setting, Bezel setting, Channel setting, Pave setting, Flush setting, Bar setting, Tension setting, Cluster setting, Illusion setting, Invisible setting.
Shallow cut---- When a diamond is cut too shallow, it will lose or leak light through the side or bottom. This results in less brilliance and value.
Shank ----The shank is the metal part of the ring worn around the finger which is cut when sized and can be replaced when worn thin.
Shape ----The outer form or appearance of a diamond; i.e.: whether the diamond is round, triangular, square, marquise, pear, oval or heart-shaped.
Sidestone----- A diamond or gemstone set alongside, or as part of a group of gemstones encircling a center stone Solitaire Typically used to describe a ring or pendant set with a single gemstone.
Step cut------- This cut is characterized by rows of facets that resemble the steps of a staircase. The emerald cut and the baguette are examples of the step cut.
Star Facet------ One of the eight triangular facets found on the upper crown section adjacent to the table of a brilliant-cut diamond. Diamond Anatomy
Stud Earring----- Small earrings that fit into the earlobes, sometimes set with gemstones
Symmetry------- The proportion of facets and finished angles created by the diamond cutter. The outstanding symmetry of a well-cut and well-proportioned diamond maximises the diamonds brilliance. Grading reports will often state the diamonds symmetry in terms of Excellent, Very good, Good, Fair, or Poor.
Table---- The top surface of a cut diamond or gemstone.
Table Percentage-------- The width of the table divided by the diameter of the Diamond. The table percentage is critical to creating sparkle in a Diamond; a Diamond with a table percentage too low or too high will lack sparkle
Table Width------ The Table width is generally given in %.It is the ratio between the width of the table to the width of the girdle or the widest point.
Tension Setting------- A setting wherein a diamond is held in place by the pressure of the bands metal, which holds the stone in a tight ‘squeeze’.
Trillion Shape----- A triangular-shaped diamond with 50 facets. Trillions are commonly used as side-stones
Wedding band---- A ring, traditionally made of precious metal, that is exchanged in a wedding ceremony
Weight Ratio------ The ratio between the diamonds weight and its diameter.
Width---- The width is the horizontal measurement of piece of jewelry. Any band or ring is measured across the widest area on the top. Settings are measured across the widest metal part, closest to where the center diamond is set.
18K Yellow Gold----- The pure version of the precious metal, unalloyed to give it a shade of bright yellow.
Zirconia, Cubic A man-made material, created in 1977, usually shaped to look similar in appearance to a diamond. It is generally called a fake diamond and is much less costly than a diamond.
A written estimate of the approximate retail replacement value of the item described.
Brilliant Cut Diamond
Crown Height Percentage
Cushion Cut Cut
Hearts & Arrows (Pattern)
Laser Drill Hole
Mine Cut Diamond
Old European Cut Diamond
Pavilion Main Facet
Does it match your politics?
Diamonds mined in war zones and sold through illegal channels are sometimes called conflict diamonds, or blood diamonds, with the profits going toward buying arms and funding insurgencies. The illegal trade often involves kidnappings, child soldiers, massacres and other atrocities. The diamond industry promotes strategies to avoid contributing to these activities, but the overall success of the industrys efforts cannot be precisely determined.
Some consumers look for better assurance that they are not supporting the underground diamond market. Diamonds mined in Many Place of world, such as the Ratnajyoti brand, are advertised as politically clean. Note that this brand says nothing about the market value of the diamond; valuation still depends on the stone's intrinsic qualities
Is the diamond treated?
Some manufacturers are proud to produce a great-looking gem at a very affordable price. They accomplish this by subjecting a diamond to treatments or enhancements to improve a gems apparent clarity or color, thus making the gem more marketable.
Yehuda diamonds, for example, are clarity enhanced. The propriety Yehuda process conceals natural flaws (by fracture filling) and makes the gem more visually appealing.
Bellataire uses HPHT (high pressure and high temperature) to improve the color of a diamond, producing a deeper or richer color. Their advertising characterizes the treatment as restoring the gem to its intrinsic beauty.
For companies like these, gem enhancement is part of their marketing strategy. However, insurers should be aware that in many other cases the presence of treatments is concealed (whether fraudulently or out of ignorance) at the point of sale. Or, by the time the gem reaches the agent's desk, the descriptive material that was part of the sale has been lost (or lost).
Because treated gems are valued at considerably less than untreated ones of similar appearance, you want to be sure of the quality of the gem you are insuring. Be certain the appraisal either states that the diamond is untreated or clearly lists the treatments.