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इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru “The Right to Information, The Right to Live” “Step Out From the Old to the New” IS 15766-1 (2007): Grading of polished diamonds, Part 1: Classifications [MTD 10: Precious Metals] “!ान $ एक न’ भारत का +नम-ण” Satyanarayan Gangaram Pitroda ““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee”” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै” Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” IS 15766 (Part 1) :2007 V1-K%7m *a-thH&T W-Jllmk!’w Indian Standard OF POLISHED DIAMONDS PART 1 CLASSIFICATION ICS 03.120.20:39.060 0 BIS 2007 BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 october 2007 PriceGroup 7 —-- .,----....... ..-.—. .—— Precious Metals Sectional Committee, MTD 1() FOREWORD This Indian Standard (Part 1) was adopted by the Bureau of Indian Standards, after the draft finalized by the Precious Metals Sectional Committee had been approved by the Metallurgical Engineering Division Council. The need for availability of diamonds of certified purity in the country is the major reason for undertaking the formulation of this standard. In the course of recent years, considerable developments have been made in the field of polished diamonds. This has resulted in an increase of number of terms used necessitating standardization of terminology on more exact basis so as to avoid ambiguity and confusion arising out of misinterpretation of terms. This standard does not relate to coloured natural diamonds. On the subject also exists an International Standard ISO/FDIS 11211-1 ‘Grading of polished diamonds — Part 1: Terminology and classification’ describing the terminology and classification that shall be used for the grading of polished diamonds. The classification of polished diamond described inthis standard are totally inline with the classification for polished diamond given inother International Standards. This standard is published in two parts. The other part in the series is: Part 2 Tests methods. The composition of the Committee responsible for the formulation of this standard is given in Annex C. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed orcalculated, expressing the result ofatest oranalysis, shall be rounded off in accordance with IS 2:1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. AMENDMENT NO. 1 JUNE 2010 TO IS 15766 (PART 1) : 2007 GRADING OF POLISHED DIAMONDS PART 1 CLASSIFICATION (Page 1 clause 2.1, line 4 ) ― Delete ‘approximately’. (MTD 10) Reprography Unit, BIS, New Delhi, India IS 15766(Part 1):2007 Indian Standard GRADING OF POLISHED DIAMONDS PART i CLASSIFICATION 1SCOPE 2.9 Internal Characteristics/Inclusions This standard specifies the terminology and 2.9.1Bearding — Tiny feathers extending in from the classification that shall be used for the grading and girdle. description of polished diamonds. 2.9.2 Bruise — Surface percussion mark, often This standard shall only be used for natural, accompanied by tiny, root-like feathers. unmounted, polished diamonds. It shall not be used 2.9.3 Cavity — Large or deep opening. for synthetic diamonds treated diamonds (other than is allowed for in 8.4), or assembled stones. 2.9.4 C/zip — Relatively shallow indentation, usually occurring along the girdle or culet. The minimum sizeofcutofpolished diamond forgrading and certification should be 0.47 cts. However simplified NOTE — An indentation could also be external. diamond reportmaybeissuedforsizesbetween 0.20 and 2.9.5 Cleavage — Large feather occurring in a plane, 0.47 cts containing statement regarding weight, colour, parallel to acrystal face. clarity, shape and measurement. 2.9.6 Cloud— Hazy ormilky area made up ofanumber 2TERMSANDDEFINITIONS of very small inclusions. For the purpose of this standard the following terms 2.9.7 Crystal — Mineral crystal included inadiamond. and definitions shall apply. 2.9.8 Feather Fracture — Separation or break due to 2.1 Diamond—Natural mineral consisting essentially either cleavage or fracture, often white and feathery in of carbon crystallized in the isometric (cubic) crystal appearance. system, with aMobs’ scale hardness of 10, a specific 2.9.9 Grain Centre — Small area of concentrated gt-mity of approximately 3.52 and a refractive index crystal structure distortion. “D’ of 2.417. 2.9.10 Graining — Internal indications of irregular 2.2 Synthetic Diamond — Man-made reproduction crystal growth. of diamond that has essentially the same chemical composition, crystal structure, optical and physical 2.9.11 Coloured Graining — Graining which appears properties as its natural counterpart. as coloured streaks. 2.3 TreatedDiamond—Diamond treated, other than 2.9.12 Re$ective Graining — Graining which appears as a reflective plane. by cutting, polishing and cleaning, to change its appearance by coating, filling, heating, irradiation or 2.9.13 Whitish Graining — Graining which may appear any other physical or chemical treatment except laser as whitish streaks or may give the stone ahazy (cloudy) drilling. appearance which decreases transparency. 2.4 PolishedDiamond—Diamond with adefined cut. 2.9.14 Indented Natural — Natural that penetrates the stone. 2.5 AssembledStone—Stone constructed of two or more parts, of which at least one is diamond synthetic NOTE — It might be considered as an external characteristic, diamond or treated diamond. depending upon depth. 2.6 Colour — Relative absence (colorlessness) or 2.9.15Knot — included diamond crystal which reaches the surface. presence of hue. 2.7 Fluorescence — Degree of luminescence of a 2.9.16 Laser Drill Hole — Tiny tube made by alaser. diamond when viewed under a long-wave ultraviolet 2.9.17 Needle — Long, thin included crystal which (UV) light source with a wavelength of 365 nm. looks like a tiny rod. 2.8 Clarity —Relative degree to which adiamond is 2.9.18 Nick — Notch near the girdle or a facet edge. free from internal characteristics/inclusions and NOTE — It may be considered as an internal characteristic, external characteristics/blemishes. Iepending upon depth. 1 IS15766(Part 1):2007 2.9.19Pinpoint — Very small inclusion, less than ten 2.13 Shape Form — Outline of a diamond when times the size normally seen as atiny dot, either singly viewed perpendicular to the table facet. or in groups or strings. 2.14 Weight — Mass of a diamond. 2.9.20 Reduced Transparency — Cloudy, milky orhazy 2.15 Diamond Loupe –- Achromatic and aplanatic, appearance of the whole or part of a diamond due to triplet type, 10x magnifying lens, the loupe of which internal features that may or may not be visible at is of a neutral tone. 10x magnification. 3TEST REPORT 2.9.21 Twinning Wisp — Inclusions located in aplane, which occur as aresult of the change in orientation of A description of a polished diamond shall be the diamond crystal structure. established by grading its criteria in accordance with the rules specified in 5 to 9 inclusive. The test shall 2.10 External Characteristics/Blemishes contain at least the following information: 2.10.1 Abrasion — Tiny nicks along the facet’s junction a) A reference to this part of IS 15766 (Part 1); or culet, producing white fuzzy lines instead of sharp b) The results of the tests specified in this part facet edges. of IS 15766 (Part 1); 2.10.2 Bruting Lines — Tiny lines on a girdle not c) Clarity; displaying a feather-like appearance. d) Colour; 2.10.3 Burn Mark — Surface clouding caused by e) Comments (if applicable); excessiw heat or uneven polished surface. f) Long-wave ultraviolet fluorescence; 2.10.4 Chip — Relatively shallow indentation, usually g) Measurements (length, breadth and height, in occurring along the girdle or culet. mm); h) Plot of internal characteristics/inclusions shall NOTE — This indentation could also be internal. be marked with red colour and external 2.10.5Extra Facet — Facet placed without regard for characteristics/blemishes shall be marked with symmetry and not required by the cutting style. green colour; 2.10.6 Natural — Part of the original crystal surface j) Proportions (table size, total height, girdle remaining on the polished stone. thickness, culet size); k) Reference code shall also be marked on the 2.10.7 Nick — Notch near the girdle or a facet edge. girdle of the diamond for example laser 2.10.8 Pit — Tiny opening, often resembling a white inscription, etc; dot. m) Shape and cut; 2.10.9 Polish Line — Tiny parallel lines left by n) Weight in carat; and polishing, fine parallel ridges confined to single facet P) Date of the test. caused by crystal structure irregularities, or tiny, parallel, polished grooves produced by irregularities 4MARKING in the scaife surface. Diamond can be certified for the colour, cut, clarity 2.10.10 Pitted Girdle — Very rough bruted girdle and carat etc. on the basis of the criteria and test method surface. as given in this Part and Part 2of this standard and the diamond item should be marked on the girdle in the 2.10.11 Scratch — Linear indentation normally seen form of laser inscription as follows: as a fine white line, curved or straight. a) First letter will denote the colour, 2.10.12 Su$ace Grain Line — Surface indication of b) Second letter denote the clarity, structural irregularity which is not seen internally and c) Third letter will denote the cut, and which may resemble faint facet-junction lines or cause a grooved or wavy surface. d) Fourth letter will denote the weight in carat. NOTE — Often the lines cross facet junctions. 5CLASSIFICATION 2.11NakedEye—Unaided eye, or eye aided through 5.1TheUseofthe WordDiamond glasses which adjust an anomalous eyesight to normal. It is unnecessary to note the genesis of a diamond as I 2.12 Cut — Shape, proportions and finish of a the use of the word diamond alone and without diamond. qualification states that it is natural. 2 IS 15766(Part 1):2007 The word diamond alone shall not be used to describe shall be carried out by a trained observer with normal synthetic diamonds irrespective of which basic material eyesight (see 2.11) and colour discrimination, under or methods are used. A product made in this way shall an artificial light source, the specification for which be clearly referred to as synthetic diamond and shall ranges from D~~to DG~[International Commission on not be graded. illumination (CIE) standard illuminant]. The colour grade shall be described by the letter or 5.2 Assembled StonesAYeated Diamonds letter range between D and Z (in capital letters), with Assembled stones and treated diamonds shall be clearly or without the colour corresponding terms given in identified and shall not be graded. Table 1. 6WEIGHT AND MEASUREMENTS 7.1.2 All Other Colours 6.1 Weight Apart from the diamonds referred to in 7.1.1 there are also diamonds that are darker in tone andlor higher in The weight of adiamond (see 2.14) shall be expressed saturation than the Zmaster stone, as well asdiamonds in metric carats (et), one carat being equivalent to with other noticeable hues or tones and these are known 200 mg (0.2 g).The weight of adiamond shall be stated as coloured diamonds. In this category, the specific in carats to two decimal places. term fancy shall precede the colour description of a NOTES — It is acceptable verbally to express one-hundredth coloured diamond. ofacarat as apoint. Weight shallberoundedupwardsifthethirddecimal is it9, 7.2 ColourGrades(Colorless toYellow,Brownand for example: Grey) a) 0.996 0.99 Ct The colour grades that shall be used are those given in b) 0.998 0.99 Ct Table 1. c) 0.999 1.00 Ct Weight may be stated using carat balance having accuracy at The German, French, Italian and Scandinavian least three decimal place. equivalent terms have been given in Annex A for 6.2 Measurements information only. The measurements of a diamond shall be expressed, 7.3 Fluorescence in millimetres, to two decimal places. Fluorescence shall be determined by comparison with The following measurements shall be contained in the a series of master stones, which themselves are a test report (see 3): derivation of those originally used to establish the a) Round shape — Minimum diameter, maximum fluorescence degrees listed below. diameter and depth (tota l height); and The degree of fluorescence shall be characterized in b) Fancy shape: length, width and depth (total accordance with Table 2. height) — Length shall be the maximum measurement in the vertical line of the plotted 8 CLARITY diagram and width shall be the maximum 8.1General measurement in the horizontal line of the plotted diagram. Clarity shall be determined by atrained observer with normal eyesight (see 2.11) using achromatic and 7 COLOUR aplanatic 10x magnification, under an artificial source of light, the specification of which is D~~ to D65 7.1General [International Commission on illumination (CIE) Diamond colours shall be divided into the followin~ standard illuminant]. two main categories. The following aspects of the internal characteristics/ NOTE — For both main categories photometric measurements inclusions and external characteristics/blemishes shall intended for colour grade determination have no conclusive be considered when determining the clarity grade: value at present. a) Size; 7.1.1Colorless to Yellow, Brown and Grey (D to Z) b) Nature; The colour of diamond within the D to Z grade range c) Number; shall be determined by visual comparison with aseries d) Position; of master stones/comparison stones which themselves are a derivation of those originally used to establish e) Brightness/colour; and the D to Z grades described in 7.2. The determination fj Mirrored images. 3 . IS15766(Part 1):2007 NOTE —Diamonds that arebeyond the 13/P 3grade areknown Table2Description ofDegreeofFluorescence asrejection grade and areconsidered asbeing outside theclarity (Clause 7.3) grading scale. Table1ISColour Grading Scale I None ornil I I Faint orslight I (Clauses 7.1.1 and 7.2) I I Medium Grade Colour Strong [ D DExceptional white plus E .----------------------------------------- ................ NOTE — The colour of fluorescence may be mentioned EExceptional white together with the degree of fluorescence. F FRare white plus G ------------------------------- --------------------------- 3) internal graining which is not reflective, GRare white H H White white or coloured and does not I ISlightly tinted white significantly affect transparency. J JSlightly tinted white b) lnternallyjlawless (IF) K KTinted white L LTinted white IF diamonds shall be free from internal M M] characteristics/inclusions and shall only N N o 0 possess external characteristics/blemishes P when examined under 10 x magnification. : Q The following does not disqualify adiamond R R from the internally flawless grade: s s Tinted T T 1) internal graining which is not reflective, u u white or coloured and does not v v significantly affect transparency. w w x x c) Loupe clean (LC) Y Y LC diamonds shall be free from internal z ZJ characteristics/inclusions when examined NOTES — For diamonds weighing under 0.47 et, the grades D (EW) and E (EW) may be combined into one under 10x magnification. The following does grade as Exceptional white or D– E, and the grades not disqualify adiamond from the loupe clean F(RW) + and G (RW) may be combined into one grade grade: as Rare white or F– G. Combined letter grade including and below may beused. 1) internal graining which is not reflective, For grades 1to L, the term equivalent colour grade may be white or coloured and does not used inconjunction with the letter grade forthose diamonds, that have brown orgrey present. significantly affect transparency. Descriptions indicating the presence of b rown or grey may d) Very very slightly includedhery very small be given for grades M and below, with or without using the letter g~ddes if the huehone description is prefixed with inclusions (V VS) “light”. V VS diamonds shall contain minute internal characteristics/inclusions when 8.2 Clarity Grades examined under 10 x magnification. V VS 1 diamonds shall contain minute The clarity grades shall be distinguished and defined internal characteristics/inclusions which as follows: shall be extremely difficult to observe a) Flawless (FL) when examined under 10 x magnification. V VS2 diamonds shall FL diamonds shall be free from internal contain minute internal characteristics/ characteristics/inclusions and external inclusions which shall be very difficult characteristics/blemishes when under 10 x to observe when examined under 10 x magnification. The following do not magnification. disqualify adiamond from the flawless grade: e) Very slightly includedhery small inclusions 1) an extra facet on the pavilion which (Vs) cannot be seen face up. VS diamonds shall contain minor internal 2) naturals totally confined to the girdle, which neither thicken the girdle nor characteristics/inclusions when examined under 10x magnification. VS1diamonds shall distort its outline. 4