What is DiamCalc and who benefits from it
What is new in the DiamCalc?
High Dynamic Range Demo movies
Caustic Movies in the next versions of DiamCalc
Scenarios - Demo files demonstraite different possibilities and effects of the program
Press Release DiamCalc 3.0 and DiamCalc 3.0 Pro launched by OctoNus
Diamond 3DBook free full version on-line
Video Tutorial - Using DiamCalc & GEM Adviser
DiamCalc Internal Cuts
External cuts (DLL)
Versions history
System requirements
Information for Mac users
Online Store
Illustrated reports
Download DiamCalc
DiamCalc 3.2 beta Documentation (PDF)
External Cuts gallery (Dll)
Online Store
Complete guide
Quick guide on Key operations (How to..)
OctoNus spread & AGS spread
Cut parameters
Cut Quality Estimation
How to Create High dynamic range (HDR) panorama
3DCalc Pro

3DCalc family
DiBox 2.0
GemAdviser Free Version
Helium IG
Helium Polish
Helium Rough
Helium Tender
M-Box 2.0
M-Box 1.5
Oxygen DZ
Oxygen HIG
Oxygen Immersion
Oxygen Inclusion
Oxygen Microscope Server
Oxygen Viewer Free Version
Oxygen XRay Server
Pacor Client
Stereo Viewer Free Version

PACOR - Advanced Computer technologies for Processing of Rough diamonds
Laser Mapping of Concavities
Scanning major and minor symmetry features
Technology patent "A method and apparatus for locating inclusions in a diamond stone"
Immersion Glass
DiamCalc Help : Cut Parameters
What is kozibe ?

Kozibe is name of optical effect like Nail Head, Fish Eye and etc.

The term Kozibe was introduced by HRD staff in Antwerp. Kozibe diamonds that show culet through crown main facets in the face-up position. In particular this phenomenon led to strong fading of crown brightness for not very big stones.

This effect is appeared only in diamonds with extra total height (big height is because of either high crown or thick girdle), and that is why it can be used as secondary negative attribute for big stones also.

The value of angle in the field Kozibe in the DiamCalc means angle of tilt when observer can see culet through crown facets.

If the value of angle is negative then it is no need to tilt because culet should be seen through all facets of crown.

Figure 1.
The photo real illustration show the kozibe effect. Crown angle is 35,00 degree, pavilion angle is 50,00 degree, culet is medium and kozibe is -1,70 degree. Obtained with DiamCalc software.

Total height
Crown height (bezel)
Crown height (valley)
Crown angle
Table diameter
Pavilion depth (mains)
Pavilion angle
Girdle valley
Square deviation
Star facets
Lower facets
Girdle (valley)
Girdle (bezel)
Fish eye
Advanced 2
Crown angle (min)
Crown angle (max)
Crown angle (avg)
Pavilion angle (min)
Pavilion angle (max)
Pavilion angle (avg)
OctoNus Spread & AGS Spread

Helium Polish cut parameters