Laboratory-Grown Diamond
UC109979
Shape
Pear
Cut
–
Carat Weight Weight
1.21ct
Polish
Excellent
Color
D
Symmetry Sym.
Excellent
Clarity
IF
Fluorescence Fluor.
None
Girdle
MED – STK
Culet
NON
Inclusion Details
–
Optical Performance Evaluation among Pear shapes
Cut Performance * Cut Perf.*
P F G VG EX OU
Fire *
P F G VG EX OU
Brilliance *
P F G VG EX OU
Optical Symmetry * O. Symmetry *
P F G VG EX OU
Spread   v2  *
0.18ct
+14.9%
Face-Up Fluorescence Face-Up Fluor.
V STR STR MED FNT NON
Detailed Compare
360 Video Pavilion
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360 Video Pavilion
Report Images
Proportions
Length × Width L × W
9.566 mm
6.019 mm
Total Height
60.74%
3.656 mm
Table
58.49%
3.521 mm
Crown Angle
34.01°
Crown Height Cr. Height
13.42%
0.808 mm
Pavilion Angle Pav. Angle
40.18°
Pavilion Depth Pav. Depth
42.72%
2.572 mm
Girdle
4.61%
0.277 mm
Culet
0.37%
0.022 mm
Certificates
GCAL 361716196
I3D Report HTML Report
Cut Performance *
Cut performance is an aggregate diamond characteristic, based on both fire and brilliance. It shows how vibrant the diamond is.
Fire *

Fire is colored flashes that we observe in colorless diamond. Perceived Fire strength depends on colored flashes quantity, size, duration, brightness, saturation and distribution.

Fire is the simultaneous (local) contrast of colour that is observed in a diamond. The contrast of this colored image depends on surrounding areas and on the duration of a colored flash.

If the colored flash is too fast the eye is not able to comprehend its colour and such a flash is perceived as scintillation. If the colored flash lasts too long its total contrast is less than the sum of the contrast of two separate shorter colored flashes of half the lifetime of the initial flash.

For a flash to be perceived as colored it should not be neither too fast, too small or too bright; when combined these factors make a colored flash appears to a human as scintillation and not a fire flash.

Brilliance *
Diamond brilliance is an illusion caused by the fact that the perceived brightness of the object significantly exceeds its actual brightness. This may occur when several parts of the object with different brightness are observed within a single space-time domain. In the case of a diamond, these parts are its virtual facets. Two virtual facets belong to the same space-time domain when an observer can not separate them due to spatial or temporal limitations of the sense of vision.
Optical Symmetry *
Optical symmetry shows how symmetric diamond looks when viewed face-up. Score is calculated from crown (ASET) image for fancy shapes and crown (ASET) and pavilion (Hearts) images for round shapes.
Spread v2 *

Diamond with the same weight can have different visible size depending on their shape. This visual size is described by spread characteristic. Positive spread means that diamond looks larger than Tolkowsky round with same weight, negative means opposite.

In Spread v2, the formula for calculating the relative Spread has been modified so that the resulting value is directly proportional to the absolute Spread, which makes the result more intuitive.

Face-up Fluorescence
Face-up fluorescence score show percentages of diamond area that belongs to different fluorescence grade for diamond image taken face-up in UV 385nm light.
Scores Description
Optical performance relative scores (grades) conversion marked with ( * ) made considering diamond shape. These grades can differ from Cutwise grades.

Absolute score (value)

Shows absolute characteristic of diamond (how much fire or brilliance is it).

Relative score (grade)

Valid for Spread v2, Fire, Brilliance and Cut Performance. Shows comparison to standard Tolkowsky round with the same visual area. For example:
Fire absolute = 1.4
Fire Score for Tolkowsky with same area 1.5
Relative = 1.4/1.5 = 0.93
Grade is calculated from Relative score. Grade marker width shows value accuracy.