BS DD 234-1996 Grading polished diamonds - Terminology and classification《分级抛光的钻石 术语和分类》.pdf

1、DRAFT FOR DEVELOPMENT DD 234:1996 ISO/TR 11211: 1995 Grading polished diamonds Terminology and classification ICS 01.040.39;39.060DD234:1996 This Draft for Development, having been prepared under thedirection of the Sector Boardfor Materials and Chemicals, was published underthe authority of the Sta

2、ndards Board and comesintoeffect on 15 June 1996 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference STI/53 ISBN 0 580 25917 X Committees responsible for this Draftfor Development The preparation of this Draft for Development was entrusted to Technical C

3、ommittee STI/53, Jewellery, upon which the following bodies were represented: Birmingham Assay Office British College of Optometrists British Horological Federation British Horological Institute British Jewellers Association British Jewellery and Giftware Federation British Retail Consortium Departm

4、ent of Trade and Industry (Laboratory of the Government Chemist) Federation of Manufacturing Opticians Joint Committee of Assay Offices of Great Britain Mail Order Traders Association National Association of Goldsmiths of Great Britain and Ireland Nickel Development Institute Sheffield Assay Office

5、Amendments issued since publication Amd. No. Date CommentsDD234:1996 BSI 02-2000 i Contents Page Committees responsible Inside front cover National foreword ii Introduction 1 1 Scope 1 2 Description of a polished diamond 1 3 Definitions 1 4 Mass (weight) and measurements 2 5 Colour 3 6 Clarity 4 7 C

6、ut 8 Annex A (normative) Clarity, polish and symmetry characteristics 14 Annex B (normative) Contents of a complete standard report 15 Figure 1 Diagram of clarity grades 8 Figure 2 Common diamond shapes 10 Figure 3 Parts and facet arrangement of a round brilliant 11 Figure 4 Proportions involved in

7、the description of a diamond 12 Table 1 GIA colour grades 4 Table 2 Corresponding terms for colour grades 5DD234:1996 ii BSI 02-2000 National foreword This Draft for Development has been prepared by Technical Committee STI/53 and is identical with ISO/TR11211:1995 Grading polished diamonds Terminolo

8、gy and classification, published by the International Organization for Standardization (ISO). ISO/TR11211:1995 was produced as a result of international discussion in which the United Kingdom took an active part. ISO/TR 11211 was prepared by ISO Technical Committee TC174, Jewellery. ISO/TR 11211 is

9、a Technical Report type1, issued as the required support for the publication of an International Standard could not be obtained, despite repeated efforts. Technical Reports of type1 are subject to review within3years of publication, to decide whether they can be transformed into International Standa

10、rds. The future of this Draft for Development is bound to ISO/TR11211 and the Draft for Development will not be reviewed or developed separately. This publication is not to be regarded as a British Standard It is being issued in the Draft for Development series of publications and is of a provisiona

11、l nature so that information and experience of its practical application may be obtained and reported to the responsible ISO Technical Committee. Users of this Draft for Development are invited to comment on its technical content, ease of use and any ambiguities or anomalies. These comments will be

12、taken into account when preparing the UK national response to ISO on the question of whether the Technical Report can be converted to an International Standard. Comments should be sent in writing to the Secretary of BSI Technical Committee STI/53, BSI,389 Chiswick High Road, London W44AL, quoting th

13、e number of this Draft for Development, the relevant clause and any proposed revision, within2years of the issue of this Draft for Development. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 15 and a back cover. This standard has been updated

14、 (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.DD234:1996 BSI 02-2000 1 Introduction This Technical Report applies to polished diamonds and was compiled by the following: Confdration internationale de la bijoute

15、rie, joaillerie, orfvrerie, des diamants, perles et pierres(CIBJO) Gemological Institute of America (GIA) International Diamond Council (IDC) Scandinavian Diamond Nomenclature (Scan.D.N.) 1 Scope This Technical Report specifies the terminology and classification to be used for the grading and descri

16、ption of polished diamonds. This Technical Report shall only be used for natural, unmounted, polished diamonds. It shall not be used for synthetic diamonds, treated diamonds (other than is allowed for in3.3), or for assembled stones (see3.5). A terminology and classification for the colour of fancy

17、coloured diamonds (see5.1.2) is in the course of preparation. Test methods concerning the technical application of this terminology and classification are in the course of preparation. 2 Description of a polished diamond A description of a polished diamond as defined in clause3 shall be established

18、by grading its criteria in accordance with the rules specified in the following clauses and shall contain mass (weight)(4.1), shape(7.2), measurements(4.2), proportions(7.3), clarity (clause6), plot of inclusions and blemishes (see6.2), colour (5.1), long-wave UV fluorescence (5.4), finish (7.4), co

19、mments (if applicable). The contents of a complete standard report are given inAnnex B. 3 Definitions For the purposes of this Technical Report, the following definitions apply. 3.1 diamond a natural mineral consisting essentially of carbon crystallized in the isometric (cubic) system. Its Mohs scal

20、e hardness is10; its specific gravity approximately3,52; and its refractive index, n D , is2,417 it is unnecessary to note the genesis of a diamond, as the use of the word “diamond” alone and without qualification states that it is naturalDD234:1996 2 BSI 02-2000 3.2 synthetic diamond a man-made rep

21、roduction of diamond which has essentially the same chemical composition, crystal structure, optical, and physical properties as its natural counterpart. It is forbidden to use the word “diamond” alone to describe synthetic diamonds that have either partly or wholly crystallized, or recrystallized,

22、due to human intervention, no matter which basic material or methods are used. Products made in this way must be clearly referred to as “synthetic diamond” 3.3 treated diamond a diamond which man has treated, other than by cutting and polishing, with the intent of changing the diamonds appearance by

23、 coating, filling or any other physical or chemical treatment NOTE 1All diamonds which man has drilled with a laser should be referred to as “clarity grade influenced by laser drilling treatment”. NOTE 2Any other treated diamonds, including those which have been coated or filled by man, cannot be gr

24、aded. 3.4 treated colour the natural colour of a diamond that has been altered by artificial means NOTE 3Those stones that owe their colour to artificially produced irradiation or any other form of treatment should only be described by their colour hue, for example “yellow treated colour”. The term

25、“fancy” should not be used. 3.5 assembled stone a stone constructed of two or more parts where at least one is diamond, whether natural, synthetic or treated. It must be clearly identified and shall not be graded 3.6 colour the relative absence (colourlessness), or presence of hue 3.7 fluorescence t

26、he degree of luminescence of a diamond when viewed under a long-wave ultraviolet (UV) light source with a wavelength of365nm 3.8 clarity the relative degree to which a diamond is free from internal characteristics/inclusions and external characteristics/blemishes 3.9 cut this is categorized by the s

27、hape, proportions and finish of a diamond 4 Mass (weight) and measurements 4.1 Mass (weight) The standard unit of mass for diamonds is the metric carat, which is equivalent to200mg(1/5g). It is acceptable to orally express one-hundredth of a carat as a “point”. The International Standard abbreviatio

28、n for carat is ct. The mass of a diamond shall be stated in carats to two decimal places. If the mass is determined with an accuracy of three decimal places, it is rounded upwards if the third decimal is a9, for example: 0,996 F 0,99 ct 0,998 F 0,99 ct 0,999 F 1,00 ctDD234:1996 BSI 02-2000 3 4.2 Mea

29、surements The measurements of a diamond are expressed in millimetres to two decimal places. The following measurements are mentioned. Round shape: minimum diameter, maximum diameter and depth (total height). Fancy shape: length, width and depth (total height). 5 Colour 5.1 General Colour refers to t

30、he relative absence (colourlessness) or presence of hue. Diamond colours can be divided into the following two main categories. For both main categories, photometric measurements intended for colour grade determination have no conclusive value at present. 5.1.1 Colourless to light yellow, light brow

31、n and light grey (D to Z) The colour of diamond within the D to Z grade range is determined by visual comparison with a series of masterstones/comparison stones which themselves are a derivation of those originally used to establish the D to Z grades described in5.2. The determination is carried out

32、 by a trained observer with normal eyesight and colour discrimination, under an artificial light source, the specification for which ranges from D 55to D 65International Commission on Illumination (CIE) standard illuminant. A colour grade shall be described by the letter or letter range between D an

33、d Z, or the letter range between D and Z together with the descriptions mentioned in the colour corresponding terms inTable 1 andTable 2. 5.1.2 All other colours The general term commonly referred to as “fancy colour” is used to describe naturally coloured yellow, brown and grey diamonds, darker in

34、tone and/or higher in saturation than the “Z” masterstone and all other naturally coloured diamonds with a noticeable hue. In this category, the specific term “fancy” may precede the colour description of a naturally coloured diamond with the respective combination of hue, tone and saturation notice

35、able when it is face up. 5.2 Colour grades (colourless to light yellow, light brown and light grey) The colour grades to be used are given inTable 1. For the corresponding terms in German, French and Italian, and the Scandinavian terms, seeTable 2. Descriptions indicating the presence of brown or gr

36、ey may be included for Grades I and below. Combined letter grades including and below M on the D to Z scale may be used as well as a two grade letter range above M. For diamonds weighing under0,47ct, the combined grades as indicated by the dashed lines D and E “exceptional white”, F and G “rare whit

37、e” may be used. 5.3 Corresponding terms for colour grades The corresponding terms in German, French and Italian, and the Scandinavian terms are given in Table 2, under the responsibility of the organizations listed in the introduction. 5.4 Fluorescence Fluorescence describes the degree of luminescen

38、ce of a diamond when viewed under a long-wave ultra-violet light source with a series of masterstones, which themselves are a derivation of those originally used to establish the fluorescence degrees listed below. The degree of fluorescence is characterized as follows: none, faint, medium, strong. T

39、he colour of fluorescence may be mentioned together with the degree of fluorescence.DD234:1996 4 BSI 02-2000 Table 1 GIA colour grades 6 Clarity 6.1 General Clarity is the relative degree to which a diamond is free from internal characteristics/inclusions and external characteristics/blemishes, when

40、 viewed by a trained observer with normal eyesight using achromatic and aplanatic 10 magnification, under an artificial source of light, the specification of which is D 55to D 65(CIE standard illuminant). The following aspects of the internal characteristics/inclusions and external characteristics/b

41、lemishes are considered when determining the clarity grade: size, nature, number, position, brightness/colour. Diamonds that are beyond theI3 or P3 grade are known as rejection grade and are considered as being outside the clarity grading scale. GIA Colour corresponding table D D Exceptional White +

42、 Colourless E E Exceptional White F F Rare White + G G Rare White Near Colourless H H White I I Slightly tinted white J J K K Tinted white Faint Colour L L M M N N O O P P Very Light Colour Q Q R R S S T T Tinted U U V V Light Colour W W X X Y Y Z ZDD234:1996 BSI 02-2000 5 Table 2 Corresponding term

43、s for colour grades GIA CIBJO/IDC Scan. D.N German French Italian D D Hochfeines Weiss + D Blanc exceptionnel + D Bianco extra eccezionale + D River E E Hochfeines Weiss E Blanc exceptionnel E Bianco extra eccezionale E River F F Feines Weiss + F Blanc extra + F Bianco extra + F Top Wesselton G G Fe

44、ines Weiss G Blanc extra G Bianco extra G Top Wesselton H H Weiss H Blanc H Bianco H Wesselton I I Leicht getntes Weiss I Blanc nuanc I Bianco sfumato I Top Crystal J J J J J Crystal K K Getntes Weiss K Lgrement teint K Bianco leggermente colorito K Top Cape L L L L L Top Cape M M M M M Cape N N N N

45、 N Cape O O O O O Cape P P P P P Cape Q Q Q Q Q Cape R R R R R Cape S S S S S Cape T T Getnt T Teint T Colorito T Cape U U U U U Cape V V V V V Cape W W W W W Cape X X X X X Cape Y Y Y Y Y Cape Z Z Z Z Z CapeDD234:1996 6 BSI 02-2000 6.2 Clarity grades (seeFigure 1) The clarity grades are distinguish

46、ed and defined as follows. Flawless (FL) Loupe Clean (LC) LC diamonds are free from internal characteristics/inclusions when examined under 10 magnification. NOTE 5The following does not disqualify a diamond from the Loupe Clean grade: internal graining which is not reflective, white or coloured and

47、 does not significantly affect transparency. FL diamonds are free from internal characteristics/inclusions and external characteristics/blemishes when examined under 10 magnification. NOTE 4The following do not disqualify a diamond from the Flawless Grade: a) an extra facet on the pavilion which can

48、not be seen face up; b) naturals totally confined to the girdle, which neither thicken the girdle nor distort its outline; c) internal graining which is not reflective, white or coloured and does not significantly affect transparency. Internally Flawless (IF) IF diamonds are free from internal chara

49、cteristics/inclusions and only possess external characteristics/blemishes when examined under 10 magnification. NOTE 6The following does not disqualify a diamond from the Internally Flawless grade: internal graining which is not reflective, white or coloured and does not significantly affect transparency. Very Very Slightly Included/Very Very Small Inclusions (VVS) VVS diamonds contain minute internal characteristics/inclusions when examined under 10 magnification. WS1 diamonds contain minute internal characteristi