Inclusions and blemishes Main article Diamond flaws There are several types of inclusions and blemishes which affect a diamond s clarity to varying degrees Features resulting from diamond enhancement procedures such as laser lines are also considered inclusions and or
blemishes Inclusions Clouds Feathers Included crystals or minerals Knots Cavities Cleavage Bearding Internal graining The diamond industry uses the term internal characteristics instead of inclusions For natural diamonds the internal characteristics in the diamond are growth crystals that give the diamond its character and unique fingerprint When diamonds are graded they are magnified at 10x power Blemishes Polish lines Grain boundaries Naturals Scratches Nicks Pits Chips Clarity grading Gemological Institute of America GIA History In 1952 Richard T Liddicoat along with Lester Bensen Joe Phillips Robert Crowningshield and Bert Krashes began to work on a new diamond grading system which they called the diamond grading and evaluation appraisal In 1953 they released their new system which assessed three aspects of diamonds make color and clarity They took terminology used in the industry at the time and refined the definitions to produce a clarity scale by which diamonds could consistently be graded The system at that time contained nine grades flawless VVS1 VVS2 VS1 VS2 SI1 SI2 I1 and I2 The I of the I1 and I2 grades stood for imperfect During the 1970s two changes were made to the system Firstly the internally flawless grade was added as GIA noticed that many diamonds were being aggressively cut to remove any surface blemishes and thereby reducing the cutting quality make of the diamonds The internally flawless grade gave diamond manufacturers a choice to leave blemishes on the surface of the stone and achieve a grade higher than VVS1 The second change made to the grading system was the introduction of the I3 grade This change was made in response to a growing number of diamonds of very low clarity being cut The last change to the clarity grading system took place in the 1990s when the term imperfect was changed to included The GIA grading system today GIA diamond clarity grading scale Category Flawless Internally Flawless Very Very Slightly Included Very Slightly Included Slightly Included Included Grade FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3 The GIA diamond grading scale is divided into six categories and eleven grades The clarity categories and grades are Flawless category FL diamonds have no inclusions or blemishes visible under 10x magnification Internally Flawless category IF diamonds have no inclusions visible under 10x magnification only small blemishes on the diamond surface Very Very Slightly Included category VVS diamonds have minute inclusions that are difficult for a skilled grader to see under 10x magnification The VVS category is divided into two grades VVS1 denotes a higher clarity grade than VVS2 Pinpoints and needles set the grade at VVS Very Slightly Included category VS diamonds have minor inclusions that are difficult to somewhat easy for a trained grader to see when viewed under 10x magnification The VS category is divided into two grades VS1 denotes a higher clarity grade than VS2 Typically the inclusions in VS diamonds are invisible without magnification however infrequently some VS2 inclusions may still be visible to the eye An example would be on a large emerald cut diamond which has a small inclusion under the corner of the table Slightly Included category SI diamonds have noticeable inclusions that are easy to very easy for a trained grader to see when viewed under 10x magnification The SI category is divided into two grades SI1 denotes a higher clarity grade than SI2 These may or may not be noticeable to the naked eye Included category I diamonds have obvious inclusions that are clearly visible to a trained grader under 10x magnification Included diamonds have inclusions that are usually visible without magnification or have inclusions that threaten the durability of the stone The I category is divided into three grades I1 denotes a higher clarity grade than I2 which in turn is higher than I3 Inclusions in I1 diamonds often are seen to the unaided eye I2 inclusions are easily seen while I3 diamonds have large and extremely easy to see inclusions that typically impact the brilliance of the diamond as well as having inclusions that are often likely to threaten the structure of the diamond GIA clarity grading procedure GIA clarity grading is performed under 10x magnification with darkfield illumination The GIA Gem Trade Laboratory uses as standard equipment binocular stereo microscopes which are able to zoom to higher magnifications These microscopes are equipped with darkfield illumination as well as an ultraviolet light filtered overhead light When grading is performed using a 10x handheld loupe darkfield illumination is more difficult to achieve The grader must use a light source in such a way that the base of the stone is lit from the side and the crown of the stone is shielded from the light After thoroughly cleaning the diamond the diamond is picked up using tweezers in a girdle to girdle hold The grader views the diamond for the first time through the table studying the culet area of the stone for inclusions The diamond is then set down and picked up with the tweezers in a table to culet hold In this position the diamond can be studied from the pavilion side and the crown side examining the diamond through each facet for inclusions Once a sector of the diamond has been thoroughly examined the grader rotates the diamond in the tweezer so that the neighboring sector can be examined The grader uses darkfield lighting to reveal characteristics and alternates to reflected overhead lighting to ascertain whether a characteristic lies within the stone on the stones surface or both If the grader is using a stereo microscope they may zoom in to a higher magnification to make closer observations of an inclusion but then return to 10x magnification to make an assessment of its impact on the clarity grade If a stereo binocular microscope has been used a final assessment using a 10x loupe is performed before the final judgment is made on the clarity of the stone The grader first decides the clarity category of the diamond using one of the keywords none FL or IF if blemished minute VVS minor VS noticeable SI or obvious I The decision is then made on the grade of the diamond http www gia edu lab reports services diamonds index html Grading systems by other organizations The clarity grading system developed by the GIA has been used throughout the industry as well as by other diamond grading agencies including the American Gemological Society AGS European Gemological Laboratory EGL and the International Gemological Laboratory IGL These grading agencies base their clarity grades on the characteristics of inclusions visible to a trained professional when a diamond is viewed from above under 10x magnification Confdration Internationale de la Bijouterie Joaillerie Orfvrerie des Diamants Perles et Pierres CIBJO CIBJO diamond clarity grading scale GIA all stones FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3 CIBJO over 0 47ct Loupe clean VVS1 VVS2 VS1 VS2 SI1 SI2 PI PII PIII CIBJO under 0 47ct Loupe clean VVS VS SI PI PII PIII The CIBJO or the International Confederation of Jewellery Silverware Diamonds and Stones developed the International Clarity Scale for grading diamonds This clarity scale mirrors the GIA grading scale except nomenclature varies The CIBJO system names these clarity grades Loupe Clean Very very small inclusions VVS1 and VVS2 Very small inclusions VS1 and VS2 Small inclusions SI1 and SI2 Pique P1 P2 and P3 Clarity grading by CIBJO standards is by examination using a 10x achromatic aplanatic loupe in normal light American Gem Society AGS diamond clarity grading scale GIA FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3 AGS 0 1 2 3 4 5 6 7 8 9 10 The American Gem Society grades clarity on a number scale between 0 and 10 These numbers grades correlate almost exactly with the GIA system but with some differences The flawless and internally flawless 0 grades are grouped together with notation defining whether the stone is free from external blemishes the VVS through SI grades are numbered 1 through 6 and then there are four grades 7 through 10 for the included category Clarity grading by AGS standards requires examination using a binocular stereo microscope equipped with adjustable zoom magnification and darkfield illumination International Diamond Council IDC IDC diamond clarity grading scale GIA FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3 IDC Loupe clean VVS1 VVS2 VS1 VS2 SI1 SI2 PI PII PIII The IDC or the International Diamond Council uses a very similar standard to CIBJO IDC loupe clean stones that have external blemishes have notations made on the grading report IDC clarity grading is by examination using a 10x achromatic aplanatic loupe in normal light European Gemological Laboratory EGL diamond clarity grading scales GIA FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3 EGL USA IF VVS1 VVS2 VS1 VS2 SI1 SI2 SI3 I1 I2 I3 EGL India FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 SI3 P1 P2 P3 The European Gemological Laboratory EGL introduced the SI3 as a clarity grade While intended as a range to include borderline SI2 I1 stones it is now commonly used to mean I1 s which are eye clean that is which have inclusions which are not obviously visible to the naked eye Clarity grading considerations All grades reflect the appearance to an experienced grader when viewed from above at 10x magnification though higher magnifications and viewing from other angles are used during the grading process The grader studies the diamond for internal characteristics and judges them on the basis of five clarity factors size number position nature and color or relief The clarity grade is assessed on the basis of the most noticeable inclusions otherwise called grade setting inclusions This means that less significant inclusions are ignored for the purposes of setting the grade However they may still be plotted onto a diamond plot chart Accurate clarity grading as with other grading steps must be done with the diamond loose meaning not set into any mounting Inclusions are often difficult to see from the crown side of the diamond and may be concealed by the setting Size The first clarity factor which is assessed is a clarity characteristic s size Larger characteristics are typically more noticeable under magnification thereby placing the diamond into a lower clarity grade Number The second clarity factor which is assessed is the number of clarity characteristics Generally the more characteristics the lower the clarity grade This assessment is made by judging how readily they can be seen not by the actual number of characteristics Position The third clarity factor which is assessed is the characteristic s position When an inclusion is directly under the table of the diamond it is most visible An inclusion under the table and positioned close to a pavilion facet will reflect multiple times around the stone giving this type of inclusion the name reflector Reflectors are graded as if each reflection were an inclusion although in plotting the diamond it is only plotted once For this reason reflectors have a greater impact on the clarity grade Inclusions become less visible when they are positioned under the crown facets or near the girdle of the stone These inclusions may often be more easily seen from the pavilion side of the diamond than from crown side of the diamond In addition the position of large feathers knots and included crystals positioned where they extend to the girdle or crown of the stone affect the clarity grade Diamonds worn in jewelry typically will withstand breakage however inclusions of this nature in these positions can pose a risk for further extension of the break in the structure of the diamond Inclusions that are judged to pose at least a moderate risk of breakage to the stone are graded in the included category Nature The fourth clarity factor which is assessed is a characteristic s nature The characteristic s nature determines whether it is internal where they extend into the stone or external where they are limited to the surface of the stone Internal characteristics automatically exclude the diamond from the flawless and internally flawless categories External characteristics exclude the diamond from the flawless category A diamond s internal characteristics can be a bruise cavity chip cleavage cloud crystal feather grain center indented natural internal graining knot laser drill hole needle pinpoint or twinning wisp A diamond s external characteristics can be an abrasion natural nick pit polish lines polish mark scratch surface graining or extra facet The nature will also detail whether an inclusion poses a risk to the stone Inclusions that cause or may cause a break in the crystal structure included crystal feather knot cleavage are considered alongside their position to assess whether they pose a moderate level of risk for further breakage Color or relief The fifth clarity factor which is assessed is the color and relief of clarity characteristics Characteristics that contrast with the surrounding diamond are said to have relief The degree to which this color and relief is noticeable affects the clarity grade of the diamond Colored inclusions invariably show contrast and are more easily seen An exception is a black pinpoint inclusion which is often more difficult to see than a white pinpoint Rarity and value Diamonds become increasingly rare when considering higher clarity gradings citation needed Only about 20 of all diamonds mined have a clarity rating high enough for the diamond to be considered appropriate for use as a gemstone the other 80 are relegated to industrial use Of that top 20 a significant portion contains an inclusion or inclusions that are visible to the naked.
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