BS ISO 24016:2020
$198.66
Jewellery and precious metals. Grading polished diamonds. Terminology, classification and test methods
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 64 |
This document specifies the terminology, classification and the methods that are used for the grading and description of single unmounted polished diamonds over 0,25 carat (ct).
This document applies to natural, unmounted, polished diamonds. It is not to be used for fancy coloured diamonds, synthetic diamonds, treated diamonds (other than is allowed for in 7.4), nor for assembled stones.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 7 | Foreword |
| 8 | Introduction |
| 9 | 1 Scope 2 Normative references 3 Terms and definitions |
| 13 | 4 General 4.1 The use of the word “diamond” |
| 14 | 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) |
| 15 | 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) |
| 17 | 6.4 Fluorescence |
| 18 | 7 Clarity 7.1 General 7.2 Clarity grades 7.3 Clarity characteristics 7.4 Laser drilling |
| 20 | 8 Cut 8.1 Cut characteristics 8.2 Shape 8.3 Proportions 8.3.1 Description 8.3.2 Basis for descriptions of proportions |
| 21 | 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 |
| 22 | 8.3.7 Culet size (percentage) and description 8.3.8 Total depth/height 8.3.9 Proportions comment |
| 25 | 8.4 Finish 8.4.1 Polish 8.4.2 Symmetry |
| 26 | 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 |
| 27 | 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 |
| 28 | 11.3.9 The grade |
| 29 | 11.3.10 Master-eye effect |
| 30 | 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 |
| 31 | 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 |
| 33 | 12.3.5 Plotting symbols |
| 35 | 12.3.6 Laser drill holes 12.3.7 Surface grain lines |
| 36 | 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 |
| 37 | 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 |
| 39 | 15.2 Polish |
| 40 | 16 Expression of results 17 Comments |
| 41 | 18 Diamond grading report |
| 43 | Annex A (normative) Clarity, polish and symmetry characteristics |
| 46 | Annex B (informative) Clarity examples |
| 63 | Bibliography |
