Glossary

EXTRA KNOWLEDGE - GLOSSARY

To better understand the intricacies of diamonds and settings, here is a useful glossary of terms.

1. Adamantine Lustre: The brilliant look of a diamond under reflected light.

2. Alluvial Diamond Mining: Mining of deposits transported by flowing water.

3. Argyle Diamond Mines: Famous WA mining complex in Kimberley Mountains.

4. Asscher Cut: A square emerald cut - wide corners, high crown and deep pavilion.

5. Baguette: A small, rectangular-to-square step cut diamond.

6. Beach Mining: The extraction of diamonds from a beach.

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: Very dark diamond that appears black due to numerous inclusions.

10. Blemish: A defect on the surface of a polished diamond.

11. Bow-Tie Effect: A dark area shaped like a bow-tie across a diamond’s centre.

12. Brilliance: The intensity of the reflections of light from the crown of a diamond.

13. Canary Diamond: An intensely yellow-coloured diamond.

14. Cape Series: Diamonds in the near-colourless to yellow colour grades (K to Z).

15. Carat Weight: The weight of a diamond expressed in metric carats.

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 brown to dark brown coloured diamond.

19. Channel Setting: A diamond setting with two parallel metal walls.

20. Clarity: A diamond’s relative lack of inclusions and blemishes.

21. Claw Setting: A set of narrow metal supports to hold diamond in place.

22. Cognac Diamond: Brown coloured diamond, also called Champagne Diamond.

23. Colour Grade: A diamond’s body colour on the colourless-to-light-yellow scale.

24. Crown: The top of the diamond above the girdle.

25. Crown Height: The distance between the girdle and the table of a diamond.

26. Crown Height Percentage: Girdle height as a percentage of the girdle diameter.

27. Culet: A small facet on the point of the pavilion (base) of a brilliant cut diamond.

28. Cushion Cut: A modified brilliant cut diamond with curved sides and rounded corners.

29. Cut: The relative proportions and finish of a polished diamond.

30. Depth: A diamond’s dimensions from the table to the culet of the diamond.

31. Diameter: The distance from one edge of the girdle to the opposite edge.

32. Diamond: Carbon crystallised at extremely high pressures and temperatures.

33. Diamond Certificate: A written report by a grading laboratory, eg. GIA.

34. Dispersion: The separation of white light into spectral colours.

35. Emerald Cut: A rectangular step cut with diagonally-cut corners.

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: Naturally coloured diamond with rare body colour.

39. Fancy Cut: Any diamond cut, or shape, other than a round brilliant cut.

40. Finish: The quality of a diamond’s polish, the girdle and the precision of the cut.

41. Fire: Rainbow prism of light reflected from a polished diamond, also known as Dispersion.

42. FL (Flawless): Diamonds with no internal or external blemishes or inclusions.

43. Fluorescence: The emission of a diamond’s visible light in high energy light.

44. Four Cs: A diamond’s four characteristics: Cut, Colour, Clarity and Carat Weight.

45. Gemological Institute of America (GIA): The world standard for diamond grading.  

46. Girdle: Narrow band which surrounds the edge of a diamond.

47. Grain Setting: A setting style where small diamonds are held by 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.

50. IF (Internally Flawless): Diamonds with no internal blemishes or inclusions.

51. Inclusion: An internal characteristic of a diamond, known as a blemish.

52. JAA: The Jeweller’s Association of Australia.

53. Laser Drilling: Process to enhance diamonds that contain dark inclusions.

54. Laser Inscription: An identifying number engraved on a diamond using a laser.

55. Length-to-Width Ratio: The comparison of the length and width of the girdle outline.

56. Loupe: A small magnifying lens used to examine a diamond.

57. Lustre: The surface appearance of a polished diamond under reflected light.

58. Marquise Cut: Boat-shaped diamond with curved sides and pointed ends.

59. Modified Brilliant Cut: Round brilliant cut with more or less facets than standard.

60. Near-Colourless: Diamonds which appear colourless when viewed from above.

61. Old Mine Cut: An early form of a brilliant cut diamond.

62. Open Pit Mining: The diamond mining process involving excavation by digging a pit.

63. Oval Cut: Brilliant cut diamond with an elliptical girdle outline from above.

64. Pavé Setting: A setting style where many small gemstones are placed close together.

65. Pavilion: The portion of a polished diamond below the girdle, i.e. the bottom section.

66. Pavilion Depth: The distance between the girdle and the culet of a diamond.

67. Pavilion Depth Percentage: Pavilion depth as a percentage of girdle diameter.

68. Pear Shape: A modified brilliant cut with pear-shaped girdle from above.

69. Piqué: European clarity grading system for diamonds with visible inclusions.

70. Plotting: Recording the type, location, size and shape of clarity characteristics.

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.

74. Proportions: The relative dimensions and angles of a polished diamond.

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.

77. Reflection: The bouncing back of light reflected from a polished diamond’s surface.

78. Rose Cut: An old cut diamond characterised by a flat base, a circular girdle, and a pointed crown.

79. Rough Diamond: A diamond excavated from the earth prior to cutting and polishing.

80. Round Brilliant Cut: Round cut diamond with circular girdle and 57 or 58 facets.

81. Scintillation: Sparkles produced when a diamond is rotated in the light.

82. Shape: The girdle outline of a diamond when viewed from above.

83. Single Cut: A cutting style with a circular girdle, table, 8 crown and 8 pavilion facets.

84. SI (Slightly Included): A GIA clarity grading for diamonds.

85. Solitaire: A ring that usually has a single diamond.

86. Step Cut: A cutting style with long, narrow facets arranged parallel to the girdle.

87. Stone: An industry term for any polished diamond.

88. Sub-Level Casing: An underground diamond mining method.

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.

92. Table Percentage:  The table size of a  diamond expressed as a percentage of the average girdle diameter of the diamond.

93. Tapered Baguette: Rectangular baguette diamond where one end is narrower than the other.

94. Total Depth Percentage: The depth of the diamond expressed as a percentage of the average girdle diameter of the diamond.

95. Trilliant Cut: A modified brilliant cut diamond with a triangular girdle outline from above.

96. Underground Mining: Mining diamonds by excavating horizontal or vertical tunnels.

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.

99. VVS (Very Very Slightly Included): A clarity grading for diamonds.