JS Grading System

Shapes

  • Round
  • Oval
  • Pear
  • Marquise
  • Emerald
  • SQ Emerald
  • Princess
  • Cushion
  • CU Brilliant
  • CU Plasma
  • Radiant
  • L Radiant
  • S Radiant
  • Heart Shape
  • Baguette

CARAT

Carat is the unit of measurement for the physical weight of diamonds.

Size +0.30 +0.40 +0.50 +0.70 +0.90 +1.00 +1.50 +2.00 +2.50 +3.00 +4.00
Size Range 0.30 to 0.399 0.40 to 0.499 0.50 to 0.699 0.70 to 0.899 0.90 to 0.999 1.00 to 1.499 1.50 to 1.999 2.00 to 2.499 2.50 to 2.999 3.00 to 3.999 4.00 to 10.999

COLOR

Diamonds that ranges from colorless to light yellow fall within the normal color range. The diamond color scale starts with the letter D and ends with Z. D-colored diamonds have the least amount of colors while Z colored diamonds have the most color. As diamonds are closer to D on the measuring scale, the more expensive they will be. Beyond the Z color, diamonds are graded as Fancy Color, which uses a separate set of parameters.

For a diamond to be more precious, they must reflect all the shades of color. Any color tint in the diamond will obstruct this. Thus, the less color there is, the more will it reflect other shades of color. Colorless diamonds are very rare. They contain little to no impurities and are essentially chemically pure. As the diamond shows more tint of color, it goes down the color grading scale.

COLOR OF DIAMONDS

Color

Diamonds

Scale

D E F

Colourless

G H I J

Near Colourless

K L M

Faint Yellow

N O P Q R

very Light yellow

S T U V W X Y Z

Light yellow

CLARITY

Virtually all diamonds contain identifying characteristics, most of them too small to be seen with the unaided eye. These "inclusions" are nature’s birthmarks; when viewed using magnification they like tiny crystals, clouds or feathers. To determine a diamond’s clarity grade, a gemologist will consider the size, number, position, color and general of any inclusions. Diamonds exhibition no such inclusions are categorized as flawless (FL) or internally flawless (IF). In general, the greater the number and size of inclusions within a diamond, the lower its clarity grade. Our diamonds are selected from the top clarity grades; any inclusions only become visible under 10x power magnification.

FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 SI3 I1 I2 I3
Flawless Internally Flawless Very Very Slightly Included-1 Very Very Slightly Included-2 Very Slightly Included-1 Very Slightly Included-2 Slightly Included-1 Slightly Included-2 Slightly Included-3 Included -1 Included -2 Included -3

CUT

Diamond cut is a style or design guide used when shaping a diamond for polishing such as the brilliant cut. Cut does not refer to shape (pear, oval), but the symmetry, proportioning and polish of a diamond. The cut of a diamond greatly affects a diamond's brilliance; this means if it is cut poorly, it will be less luminous.

EX
Excellent
VG
Very Good
G
Good
F
Fair

POLISH

Polish refers to the degree of smoothness of each facet of a diamond as measured by a gemologist. When a diamond is cut and polished, microscopic surface defects may be created by the polishing wheel as it drags tiny dislodged crystals across the diamond's surface. Depending on the severity, these defects may disrupt light patterns as the light rays enter and exit the diamond.

EX
Excellent
VG
Very Good
G
Good
F
Fair

SYMMETRY

Symmetry refers to how precisely the various facets of a diamond align and intersect. This can include extra or misshapen facets, off centre culets and tables, and wavy girdles.

A diamond with poor symmetry may misdirect light that travels into the diamond, sending it off at slightly wrong angles, and thereby reducing the diamond's brilliance. Often, a diamond cutter will purposefully allow a minor reduction in symmetry as a way of preventing a defect present in the rough stone from being retained as part of the finished diamond.

EX
Excellent
VG
Very Good
G
Good
F
Fair

FLUORESCENCE

Fluorescence is a greatly misunderstood concept. Fluorescence is the reaction of trace minerals within the diamond that cause the diamond to glow when exposed to ultraviolet light. In the laboratory, special ultraviolet lamps are used to check for this but the sun is also a source of ultraviolet rays so diamonds will react in daylight as well. About one third of all diamonds fluoresce. Of these, the most common color is blue, but diamonds can fluoresce other colors. More than 95% of those that do fluoresce will fluoresce blue. The next most common color is yellow. Any other color of fluorescence would be rare.

N
None
F
Faint
M
Medium
ST
Strong
VST
Very Strong

WHITE INCLUSION

There is two part of inclusion (1) Table white (2) Side white. We grade diamonds on the basis of white inclusions as compared to the total inclusions by determining the following categories.

N
None
PP1
minor
PP2
Medium
CRL1
Minor
SPR1
Minor
SPR2
Medium
FR1
Minor
FR2
Medium

BLACK INCLUSION

There is two part of inclusion (1) Table Black (2) Side Black. We grade diamonds on the basis of black inclusions as compared to the total inclusions by determining the following categories.

N
None
B_PP
Black Pin Point
B1
Minor
B2
Medium

MILKY

Milkiness is mainly a hazy inclusion in the diamond that appears white or grey in color. This haziness affects the brilliance of a diamond. Such diamonds are further classified based on the magnitude of milkiness.

ML1
Slighty Milky
ML2
Medium Milky
ML3
Heavy Milky

HEART & ARROWS

The hearts and arrows pattern (often marketed under brand names such as 'Hearts on Fire') refers to a symmetrical light pattern visible using a specialized viewer in diamonds cut within certain narrow specifications.

N
None
EX
Excellent
VG
Very Good
G
Good
F
Fair

LUSTER

Luster and brilliance are two most valued attributes of a diamond. Luster describes a diamond’s fire and sparkle. Depending upon the light reflected from the stone, JSG grades diamonds on the basis of two levels of luster:

EX
Excellent
VG
Very Good
G
Good

OPEN INCLUSION

There is two part of Open inclusion (1) Table Open Inclusion (2) Side Open Inclusion. Open inclusion is the inclusion on the surface of a diamond. Under JSG, diamonds with open inclusions are graded as mentioned below:

N
None
HL
HairLine
SM
Small
MED
Medium
HV
Heavy

Extra-Facet

It is an extra facet that is placed on a diamond’s normal facet without considering the symmetry of the stone. These are additional to the facets required for making a brilliant cut diamond.

N
None
PSM
Small
PMD
medium
PMJ
Major
PHV
Heavy
CSM
Small
CMD
Medium
TSM
Small

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