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    Education Centre

    Diamond Glossary

    To further help you with your diamond education, Diamond Exchange has compiled this useful glossary of terms commonly used when dealing with diamonds and precious stones. 

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    1. Adamantine Lustre: The brilliant look of a diamond’s surface under reflected light.
    2. Alluvial Diamond Mining: The excavation mining of deposits which have been transported and concentrated by flowing water.
    3. Argyle Diamond Mines: The mining complex 2,400km north of Perth in Western Australia’s Kimberley Mountains.
    4. Asscher Cut: A square emerald cut with wide corners, a high crown and a deep pavilion. (For more details, refer to Shapes Explained.)
    5. Baguette: A small, rectangular-to-square step cut diamond that is sometimes tapered.
    6. Beach Mining: The extraction of diamonds from the section of a beach that is left uncovered between high and low tides.
    7. Bearded Girdle: A girdle with a rough finish.
    8. Bezel Setting: A thin strip of metal encircling a stone to secure it in a setting.
    9. Black Diamond: A very dark diamond that appears black and opaque due to numerous inclusions, which block the transmission of light through, within and out of the diamond.
    10. Blemish: A term used by the GIA to describe a defect on the surface of a polished diamond.
    11. Bow-Tie Effect: A dark area resembling a bow-tie that can be sometimes seen through the table across the centre of a marquise, oval- or pear-shaped diamond.
    12. Brilliance: The intensity of the internal and external reflections of light from the crown of a polished diamond.
    13. Canary Diamond: A term used to describe an intensely yellow-coloured diamond.
    14. Cape Series: The range of diamonds that fall in the near-colourless to yellow colour grades (K to Z).
    15. Carat Weight: The weight of a diamond expressed in metric carats. (For more details, refer to Diamonds Explained.)
    16. Carbon Spot: A misnomer for a black inclusion found in a diamond.
    17. Carré Cut: A square step-cut diamond.
    18. Champagne Diamond: A light to dark brown coloured diamond, also called a Cognac Diamond.
    19. Channel Setting: The setting style in which diamonds are set between two parallel metal walls with no metal in between.
    20. Clarity: A diamond’s relative freedom from inclusions and blemishes. (For more details, refer to Diamonds Explained.)
    21. Claw Setting: A set of narrow metal supports, also known as prongs, that holds the diamond in place.
    22. Cognac Diamond: A light to dark brown coloured diamond, also called a Champagne Diamond.
    23. Colour Grade: The relative position of a diamond’s body colour on a colourless-to-light-yellow scale. (For more details, refer to Diamonds Explained.)
    24. Crown: The part of the diamond above the girdle, i.e. the top of the diamond.
    25. Crown Height: The distance between the girdle and the table of a diamond.
    26. Crown Height Percentage: The distance between the girdle and the table of a diamond, expressed as a percentage of the average girdle diameter.
    27. Culet: A small facet on the point of the pavilion of a brilliant cut diamond, i.e. the point at the bottom of a diamond.
    28. Cushion Cut: A modified brilliant cut diamond with curved sides and rounded corners. (For more details, refer to Shapes Explained.)
    29. Cut: The relative proportions and finish of a polished diamond. (For more details, refer to Diamonds Explained.)
    30. Depth: The dimension of a diamond from the table to the culet of a diamond.
    31. Diameter: The distance from one edge of the girdle on a diamond to the opposite edge.
    32. Diamond: A mineral composed of carbon crystallised at extremely high pressures and temperatures.
    33. Diamond Certificate: A report written by a grading laboratory, such as the Gemological Institute of America. (For more details, refer to Diamond Certificates.)
    34. Dispersion: The separation of white light into spectral colours.
    35. Emerald Cut: A rectangular step cut with diagonally-cut corners. (For more details, refer to Shapes Explained.)
    36. Facet: A flat polished surface on a finished diamond.
    37. Faceted Girdle: A girdle that has been polished with a series of flat facets.
    38. Fancy Coloured Diamond: Any naturally coloured diamond with a noticeable depth of body colour that is considered to be rare, i.e. pink of blue.
    39. Fancy Cut: Any diamond cut, or shape, other than a round brilliant cut. (For more details, refer to Shapes Explained.)
    40. Finish: The quality of a diamond’s polish, the condition of the girdle and the precision of the cut.
    41. Fire: The rainbow prism of light that is reflected from a polished diamond, technically known as Dispersion. The better a diamond is cut, the more fire is emitted from the diamond. 
    42. FL (Flawless): the clarity grade applied to diamonds with no internal or external blemishes or inclusions.
    43. Fluorescence: The emission of visible light by a diamond when stimulated by high energy light such as UV. Fluorescence rarely affects a diamond’s sparkle and brilliance, and can make warmer/lower-coloured diamonds look whiter and more colourless.
    44. Four Cs: The four characteristics which determine the quality and value of a diamond: Cut, Colour, Clarity and Carat Weight. (For more details, refer to Diamonds Explained.)
    45. Gemological Institute of America (GIA): A non-profit educational institution that was established in 1931 to serve the diamond industry and the public. The GIA’s grading scales have become the standard for diamond grading all over the world.
    46. Girdle: Narrow band which surrounds the edge of a diamond separating the crown (top) from the pavilion (bottom).
    47. Grain Setting: The setting style in which small diamonds are held in place with small beads of metal.
    48. Hardness: A diamond’s resistance to scratching and abrasion.
    49. Heart Shape: A modified brilliant diamond cut into the shape of a heart. (For more details, refer to Shapes Explained.)
    50. IF (Internally Flawless): The clarity grade applied to diamonds with no internal blemishes or inclusions.
    51. Inclusion: An internal characteristic of a diamond, otherwise referred to as a blemish.
    52. JAA: The Jeweller’s Association of Australia.
    53. Laser Drilling: An enhancement process used to improve the appearance of diamonds that contain dark inclusions.
    54. Laser Inscription: An identifying number or message engraved on a diamond (usually on the girdle) using a laser.
    55. Length-to-Width Ratio: The comparison of the length and width of the girdle outline when viewing a non-round shaped diamond from above, determined by dividing the length by the width (the width is expressed as 1).
    56. Loupe: A small magnifying lens used to examine a diamond.
    57. Lustre: The appearance of the surface of a polished diamond under reflected light.
    58. Marquise Cut: A modified brilliant cut boat-shaped diamond with curved sides and pointed ends. (For more details, refer to Shapes Explained.)
    59. Modified Brilliant Cut: A diamond cut based on the round brilliant cut, but with either more or less facets than the standard 58 (or 57).
    60. Near-colourless: The term used to describe diamonds which appear colourless when viewed from above.
    61. Old Mine Cut: An early form of a brilliant cut diamond with a nearly cushion-shaped girdle outline when viewed from above, a high crown, a small table, a deep pavilion and a large culet.
    62. Open Pit Mining: The diamond mining process involving excavation by digging a pit.
    63. Oval Cut: A modified brilliant cut diamond with an elliptical girdle outline when viewed from above. (For more details, refer to Shapes Explained.)
    64. Pavé Setting: The setting style in which many small gemstones are placed closely together.
    65. Pavilion: The portion of the polished diamond below the girdle, i.e. the bottom section of the diamond.
    66. Pavilion Depth: The distance between the girdle and the culet of a diamond.
    67. Pavilion Depth Percentage: The distance between the girdle and the culet of a diamond, expressed as a percentage of the average girdle diameter on round brilliant cuts, and as a percentage of the width on non-round shaped diamonds.
    68. Pear Shape: A modified brilliant cut with one rounded end and one pointed end which as a pear-shaped girdle outline when viewed from above. (For more details, refer to Shapes Explained.)
    69. Piqué: A French word, meaning ‘pricked’. A European clarity grading system abbreviated to P1, P2 and P3, and is applied to diamonds with inclusions visible to the naked eye. The GIA clarity grade equivalents are I1, I2 and I3.
    70. Plotting: The process of recording the type, location, size and shape of clarity characteristics of a diamond on a facet diagram.
    71. Polish: The condition of the facet surfaces on a polished diamond.
    72. Polished Girdle: A girdle that has been finished to a smooth surface.
    73. Princess Cut: A square modified brilliant cut, usually with 57 facets. (For more details, refer to Shapes Explained.)
    74. Proportions: The relative dimensions and angles of a polished diamond and the relationship between them.
    75. Quality: The relative excellence of a diamond’s cut, colour and clarity.
    76. Radiant Cut: A square or rectangular modified brilliant cut with the corners trimmed. (For more details, refer to Shapes Explained.)
    77. Reflection: The bouncing back of light when reflected from a polished diamond’s surface.
    78. Rose Cut: An old cut characterised by a flat base, a circular girdle, a pointed domed crown and a varying number of triangular facets.
    79. Rough Diamond: A diamond as it is recovered from the earth prior to undergoing cutting and polishing.
    80. Round Brilliant Cut: the standard round cut diamond with a circular girdle and 57 or 58 facets, as it may or may not have a culet. (For more details, refer to Shapes Explained.)
    81. Scintillation: The sparkles and flashes that a diamond produces when it is tilted or rotated in the light, giving a diamond its beauty.
    82. Shape: The girdle outline of a diamond when viewed from above.
    83. Single Cut: A cutting style with a circular girdle, a table, eight crown facets and eight pavilion facets.
    84. SI (Slightly Included): A GIA clarity grading for diamonds. (For more details, refer to Diamonds Explained.)
    85. Solitaire: A ring that usually has a single diamond.
    86. Step Cut: A cutting style in which long, narrow, four-sided facets are arranged in rows parallel to the girdle on both the crown and the pavilion, i.e. Emerald cut or Baguette cut.
    87. Stone: A diamond industry term for any polished diamond.
    88. Sub-Level Casing: An underground diamond mining method in which ore drilled and blasted loose at one level is then dropped through a slot to a level below, there to be collected and transported to the surface.
    89. Symmetry: The grading term for the exactness of shape and placement of facets.
    90. Table: The large facet in the centre of the crown of a polished diamond.
    91. Table Diameter: The distance between any two opposing sides of the table on a round brilliant cut diamond.
    92. Table Percentage:  For round brilliant cuts, the size of the table expressed as a percentage of the average girdle diameter.
    93. Tapered Baguette: A modification of the rectangular baguette in which one end is narrower than the other.
    94. Total Depth Percentage: The depth from the table to the culet, expressed as a percentage of the average girdle diameter of a round brilliant cut, and as a percentage of the girdle width on non-round diamonds.
    95. Trilliant Cut: A modified brilliant cut with a triangular girdle outline when viewed from above.
    96. Underground Mining: A process of mining diamonds by excavating horizontal or vertical tunnels and bringing the ore and associated minerals to the surface.
    97. Under Rail: The bar(s) of metal beneath the centre setting of a ring.
    98. VS (Very Slightly Included): a clarity grading for diamonds. (For more details, refer to Diamonds Explained.)
    99. VVS (Very Very Slightly Included): A clarity grading for diamonds. (For more details, refer to Diamonds Explained.)

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