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BS ISO 24016:2020 Jewellery and precious metals. Grading polished diamonds. Terminology, classification and test methods >
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BS ISO 24016:2020 Jewellery and precious metals. Grading polished diamonds. Terminology, classification and test methods, 2020
- undefined
- Foreword
- Introduction
- 1 Scope
- 2 Normative references
- 3 Terms and definitions
- 4 General
- 4.1 The use of the word “diamond”
- 4.2 Composite stones/assembled stones
- 5 Mass and measurements
- 5.1 Mass
- 5.2 Measurements
- 6 Colour
- 6.1 General
- 6.1.1 Colourless to yellow, brown and grey (D to L)
- 6.1.2 Colourless to yellow, brown and grey (M to Z)
- 6.1.3 Other hues
- 6.2 Colour grades (colourless to yellow, brown and grey)
- 6.3 Colour grades (other than for yellow, brown and grey)
- 6.4 Fluorescence
- 7 Clarity
- 7.1 General
- 7.2 Clarity grades
- 7.3 Clarity characteristics
- 7.4 Laser drilling
- 8 Cut
- 8.1 Cut characteristics
- 8.2 Shape
- 8.3 Proportions
- 8.3.1 Description
- 8.3.2 Basis for descriptions of proportions
- 8.3.3 Table size (percentage)
- 8.3.4 Crown height (percentage) and/or crown angle (degrees)
- 8.3.5 Pavilion depth (percentage) and/or pavilion angle (degrees)
- 8.3.6 Girdle thickness (percentage) and description
- 8.3.7 Culet size (percentage) and description
- 8.3.8 Total depth/height
- 8.3.9 Proportions comment
- 8.4 Finish
- 8.4.1 Polish
- 8.4.2 Symmetry
- 9 Identification
- 10 Testing mass and measurements
- 10.1 Testing mass
- 10.2 Testing measurements
- 11 Testing and grading colour and fluorescence
- 11.1 Cleaning of masterstones
- 11.2 Masterstones for colour
- 11.3 Procedure
- 11.3.1 Precautions
- 11.3.2 Cleaning
- 11.3.3 Comparisons
- 11.3.4 Round stones
- 11.3.5 Fancy shapes
- 11.3.6 Colours
- 11.3.7 Lighting
- 11.3.8 Positioning
- 11.3.9 The grade
- 11.3.10 Master-eye effect
- 11.4 Description of fluorescence
- 11.4.1 Equipment and References
- 11.4.2 Masterstones for fluorescence
- 11.4.3 Working conditions and methodology
- 11.4.4 Fluorescence, other than blue
- 12 Testing and grading clarity
- 12.1 General
- 12.2 Apparatus
- 12.3 Procedure
- 12.3.1 General
- 12.3.2 Lighting
- 12.3.3 Distance
- 12.3.4 Plotting
- 12.3.5 Plotting symbols
- 12.3.6 Laser drill holes
- 12.3.7 Surface grain lines
- 12.3.8 Internal graining
- 12.3.9 General
- 13 Testing shape
- 14 Testing and grading proportions
- 14.1 Appropriate instruments
- 14.2 Description
- 14.2.1 Table sizes
- 14.2.2 Crown height
- 14.2.3 Pavilion depth
- 14.2.4 Girdle thickness
- 14.2.5 Culet size
- 14.3 Proportions comments
- 15 Grading of symmetry and polish (Finish)
- 15.1 Symmetry
- 15.2 Polish
- 16 Expression of results
- 17 Comments
- 18 Diamond grading report
- Annex A (normative) Clarity, polish and symmetry characteristics
- Annex B (informative) Clarity examples
- Bibliography [Go to Page]
