diamond grading chart - investiční zlato · carat the weight of a diamond is expressed in carats....
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Diamond Grading Chart
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NBN EN ISO/IEC 17025 NBN EN ISO/IEC 17025
www.hrdantwerp.be
NBN EN ISO/IEC 17025
www.hrdantwerp.be
NBN EN ISO/IEC 17025 NBN EN ISO/IEC 17025
www.hrdantwerp.be
NBN EN ISO/IEC 17025
Belgium - China - Hong Kong - India - Middle East
CaratThe weight of a diamond is expressed in carats. One carat = 0.2 grams and one carat equals 100 points.
.05 .10 .15 .20 .25 .50
EXC.WHITE+
EXC.WHITE
ED
HEART RADIANTEMERALD PRINCESS
RAREWHITE+
F
RAREWHITE
G
WHITE
H
SLIGHTLY TINTED WHITE
I J
TINTED WHITE
K L M N-O P-R S-Z
TINTED COLOUR
.75 1.00 1.25 1.50 1.75 2.00 2.50 3.00 4.00 5.00 7.00
ClarityAll diamonds have traces of their growth history. In gem-quality diamonds, this concerns minute internal and external characteristics, graded under Clarity.
The clarity scale reflects the size, number, location and visibility of the characteristics when examined with a loupe 10 X. The very best - and rarest - clarity is loupe clean. Most inclusions, however, are not visible to the naked eye. Diamonds that have no inclusions visible to the unaided eye are also of excellent value.
ColourMost diamonds are colourless to slightly yellowish. The colourgrade is determined by comparison with a series of masterstones, the best grade being colourless (D, exceptional white +).
Diamonds can also occur in all sorts of colours, ranging from brownish to striking yellows, pink to purple, red and blue. These are called “fancy colours”. Certain diamonds can react to “black light” with grades varying from nil-slight-medium to strong. Besides colour, the fluores-cence of the diamond is also graded.
LC VVS1 VVS2 VS1 VS2 SI1 SI2 P1 P2 P3
ROUNDBRILLANT
OVAL PEARMARQUISEGRIDLE THICKNESS
GRIDLE THICKNESS
% Øt
% hc
% hp% td
Ø (100%)
ß∂
% Øt
CutFire, brilliancy andscintillation of adiamond are largelydetermined by theproportions of variousparts of the stone. Finish grade mainly evaluates the symmetry.
Shape Diamonds can be cut in various shapes (e.g. square, pear or heart). The round brilliant is probably the best known shape.
proportions & finish grade
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Education
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Research
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Equipment
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China
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India
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www.hrdantwerp.be
NBN EN ISO/IEC 17025 NBN EN ISO/IEC 17025
www.hrdantwerp.be
NBN EN ISO/IEC 17025
HRD Antwerp Contacts
www.hrdantwerp.be
NBN EN ISO/IEC 17025 NBN EN ISO/IEC 17025
www.hrdantwerp.be
NBN EN ISO/IEC 17025
Belgium - China - Hong Kong - India - Middle East