Glossary of Terms

Important glossary of terms
10x magnification
The degree of magnification used to grade the clarity of diamonds.
14 karat (.585)
Refers to the purity of gold in an item based on 24 karat being pure gold. 14 karat gold is 14 parts gold, 10 parts alloy which equates to approximately 58.5% pure gold (.585).
18 karat (.750)
Refers to the purity of gold in an item based on 24 karat being pure gold. 18 karat gold is 18 parts gold, 6 parts alloy, which equates to 75% pure gold (.750).
Alluvial deposit
All gem deposits that are created by erosion. Many diamonds are found in alluvial deposits.
Binocular microscope
An instrument used in gemology to view gemstones under magnification.
A term used for a surface imperfection on a gemstone. A blemish may be natural or induced by man.
Is the reflection of white light both internally and externally from a gemstone in the face up position.
Carat Weight
The unit of measurement used to weigh diamonds and colored stones. One carat weighs 1/5 gram or 200 milligrams.
A growth characteristic found in diamond that appears black when viewed. Carbon is a non metallic chemical element. Carbon in a crystalline form is diamond.
Clarity Grade
Refers to the degree of inclusions or blemishes in a particular diamond based on a scale from Flawless through Imperfect.
A fracture in a diamond that runs parallel to a separation plane.
A group of inclusions that together give a cottony appearance in a transparent gemstone. A cloud may be very difficult to see, or may consume an entire stone and have an undesirable effect on its brilliance.
A diamond is graded on a scale that ranges from colorless through shades of yellow, gray or brown. The ideal diamond will fall in the colorless range. There are also fancy colored diamonds. These diamonds can be found in a broad range of body color such as desirable yellows, blues, pinks etc. Fancy color diamonds may be more valuable than colorless diamonds based on the intensity of color.
The portion of a gemstone that is above the girdle.
Cubic or isometric system
The molecular arrangement in which diamonds crystallize.
A facet polished at the base of the pavilion in a gemstone.
Cut refers to the ability of a diamond to return optimal brilliance and dispersion of light to the eye based on specific proportions. These proportions are imposed by the cutter of a particular diamond.
A measurement expressed as a percentage of a gemstone's depth in relationship to its diameter.
Diamond Grading
We believe at ICE RIVER DIAMONDS that our customers should have a better understanding of how diamonds are graded so that a more educated approach may be taken when selecting a diamond. Many terms have been used to describe diamonds. Originally diamonds were described by the mines that they were believed to have come from. Depending on geographic location certain characteristics were more prevalent and believed to influence the diamonds from that region -especially in terms of color grading. These terms have originated over hundreds of years. Today, various companies and institutions have created grades specific to individual diamonds verses terms used to describe a particular mine or region. We believe the degree of accuracy varies among some of these companies and institutions. Therefore, at ICE RIVER DIAMONDS you will only find diamonds graded through the Gemological Institute of America. It is our opinion that GIA certifications have highest standards of integrity and consistent accuracy in the industry. GIA is a world leader in diamond grading.

Diamonds are graded for color, clarity, cut, and carat weight. In terms of color, GIA grades diamonds from colorless through yellow or brown. In addition, diamonds that reach a certain intensity and hue are called fancies, i.e. yellow diamonds.
Diamond Shapes
Round diamonds are the most popular of all the shapes, perhaps because their circular proportions display the most "fire" and reflect more light back to the observer than any other shape. Round diamonds require that more rough be removed during cutting and polishing than with other shapes. The combined popularity of round diamonds and the significant weight loss during cutting are the two main contributing factors to the relatively higher price of these stones.

The Princess cut is a square cut with sharp edges. It has very good fire and a high degree of brilliance. The princess cut utilizes most of the original shape of the rough diamond and the weight loss from cutting is low. As a result, its price is usually more attractive than a comparative round cut with the same weight.

Length to width ratio A princess cut with a length to width ratio of less than or equal to 1.05:1 will appear square to the observer. While a squarer diamond is the preference of many, some people prefer a slightly rectangular-shaped princess diamond.

The Oval cut is elliptical in shape and is a variation of the round brilliant cut diamond. The oval shaped diamond gives a flattering illusion of length to the finger and hand, and is popular among women with small hands or short fingers. It can also accentuate long, slender fingers.

Length to width ratio An oval cut with a length to width ratio of approximately 1.40 - 1.60 (the average of 1.50 is shown in blue) is the preference of most diamond buyers. For those who prefer a rounder look, choose a ratio closer to 1.15:1. For those who prefer a more elongated shape, look for a ratio of 1.70:1

The Pear cut is a tear-drop shape and is a variation of the round brilliant cut diamond. This attractive diamond is also extremely well-suited to pendants and earrings. Many of the largest stones ever discovered have been cut and faceted into magnificent pear-shapes.

Length to width ratio Most people prefer a pear-shaped diamond to have a length to width ratio of approximately 1.65:1. More elongated pear-shapes extend to a ratio of 1.80:1, whereas a more compact look is achieved with a ratio closer to 1.20:1

Emerald cuts are sleek and elegant. The Emerald cut is rectangular with cut corners. It is a step cut - its facets being broad with flat planes resembling the steps of a stair. Higher quality Emerald cuts are preferred because its cut makes inclusions and lower color grades more noticeable than with other cuts.

Length to width ratio An emerald cut with a length to width ratio of approximately 1.35:1 is generally the most prized. However, in recent years, square emerald cuts have become extremely popular.

The ultimate symbol of love, the romantic Heart shape is a variation of the round brilliant cut diamond.

Length to width ratio A heart-shaped stone is usually proportioned with equal length and width, approximating a ratio of 1:1. A length to width ratio of between 0.90:1 and 1.15:1 is preferred. The ratio should not fall below 0.80:1 or exceed 1.20:1

The Marquise cut is boat shaped and is a variation of the round brilliant cut diamond. Marquise cuts are often chosen by woman who wish to display an independence of style. Its elongated form can create the illusion of longer, narrower fingers.

Length to width ratio A marquise cut with a length to width ratio of approximately 2:1 is the norm. For those who prefer a rounder look, choose a ratio closer to 1.5:1. For those who prefer a more elongated shape, look for a ratio of 2.25:1

The cushion cut is an antique-style diamond cut that has recently come back into fashion. It is a cross between an Old Mine Cut (a deep cut with a high crown and large facets that was common in the late 19th and the early 20th centuries), and a modern oval cut. The cushion shaped diamond is squarish with rounded corners and sides. This cutting style has a slightly softer brilliance compared with newer modern cuts. The cushion cut diamond has grown in popularity for its "old-world" femininity and elegant appeal.

Length to width ratio Squarer-looking cushion cuts (Ratio of 1:1) tend to be prefered to more rectangular ones (Ratio of 1.2:1). Cushion cuts should not exceed a ratio of 1.2:1

This is a modified or combination cut - a brilliant cut square or rectangle shaped diamond with clipped-off corners like the emerald cut. It melds the elegance of the emerald cut diamond with the brilliance and sparkle of the round diamond.

Length to width ratio A radiant cut with a length to width ratio of less than or equal to 1.05:1 will appear square to the observer. While a squarer radiant-cut diamond is the preference of many, some people prefer a slightly rectangular diamond.

The Asscher cut is a variant of the emerald cut and provides a uniquely regal and elegant look to its wearer. Its art-deco styling combines old-world charm with modern cutting and faceting techniques to produce a dazzling example of brilliance.

Length to width ratio Very Square Asscher cuts (Ratio of 1:1) are prefered to even slightly more rectangular looking ones. Asscher cuts should not exceed a ratio of 1.1:1.

Triangle (Trilliant)
This is a brilliant-cut triangle diamond - a wedge shape with fiery brilliance. It can be a traditional triangular shape with pointed corners, or a more rounded triangular shape. Trilliants (also called Trillions) are often used as diamond accents in three stone rings and other jewelry settings, but may also be chosen to be set as solitaire diamonds.

Length to width ratio An equilateral triangle is prefered in a trilliant diamond. Variance in the ratio of length to width should not deviate considerably.
Is the ability of a transparent gem to break up white light into colors of the visible light spectrum.
A polished surface cut on a diamond or gemstone.
Fancy shape
Refers to any cut shape of diamond other than round brilliant.
Described as a break in a diamond that can be viewed at right angles of a separation plane.
The external grade of a diamond based on its symmetry, excellence of its polish, and smoothness of its faceting.
A gemstone's reaction to ultraviolet radiation. A diamond may react to various degrees when exposed. The greater the reaction, the less valuable a diamond is.
Abbreviation for the Gemological Institute of America.

The outer edge of a gemstone, the part that separates the crown from the pavilion.
The characteristic crystal form in which diamonds grow in the earth. This common growth formation of diamonds is the octahedron.
The degree of a gemstone's resistance to being scratched by another material. The Moh’s hardness scale rates gemstones on a scale of 1 -10. On this scale, 1 is the softest and 10 is the hardest.
A natural growth characteristic found within the structure of a gemstone.
The name applied to the type of igneous rock that diamonds are found in.
Laser inscription registry
An inscription located on the girdle of a diamond, usually consisting of a series of numbers or symbols. These numbers and symbols link a particular diamond to a specific grading certificate.
An instrument used to measure gemstones to an accuracy of 1/100th of a millimeter.
A unit of measurement that is equal to 1/10th of a centimeter.
A small area on a fashioned diamond left by the cutter to retain weight from the original rough. Naturals are most prevalent within the width of the girdle.
The most common shape that diamonds grow into.
The part of the diamond that is below the girdle.
A a small rounded inclusion in a diamond that is not large enough to be called an included crystal.
Platinum is a white colored precious metal used to make jewelry. Platinum is known for its long-term wear ability.
A unit of measurement used to define the weight of a gemstone that equals 1/100 of a carat.
The degree in which the finished surface of gemstones approaches optical perfection.
Refractive index
The measurement of a gemstone's ability to bend light as it passes through the stone. The degree in which a gemstone bends light can be used to identify it.
Uncut diamonds or colored stones. The natural condition in which a diamond or gemstone is found in the ground.
Round Brilliant
The most common shape of cut diamonds. A standard round brilliant diamond consists of 58 facets
The visibility of the brilliance and dispersion of light when a diamond is under movement.
Specific gravity
The density of any substance in relation to water at 4 degrees celsius. Diamonds have a density of 3.52.
A gemstone's reaction to the exposure of various external elements such as acid, sunlight, heat, etc.
The alignment and shape of facets on a diamond. This can affect the optimal beauty on the diamond.
The large facet that caps the top of the crown in a diamond or gemstone.
Refers to a gemstone's ability to remain intact under duress.
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