What is Helium Polish and who benefits from it
What is new in the Helium Polish?
Versions history
Documentation for Helium Polish releases
Advantages for analyzing girdle asymmetry and removing girdle asymmetry
Scanning major and minor symmetry features
Measuring diameter of girdles with a conical shape, "CZ" sample
Photoreal image of Helium Polish 3D model
What is new in the Helium Polish reports?
Reports history

Customizing printing and viewing reports
Customizing export data
Customizing MS Word report templates
Customizing internal text report template
Helium Polish Illustrated reports (one page reports)
Reports for semipolished diamonds and arbitrary cuts
Recut reports
Helium Polish download

Helium Polish Highlights (PDF)
Helium Polish system manual (PDF)
Helium reports documentation (PDF)
Cut parameters
Creating and customizing pricelists (PDF)
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
Helium polish product features
Measuring diameter of girdles
with a conical shape, "CZ" sample

We wish to explain a problem with measurement of diameters that can result in differences between manually measured and Helium scanned diameters. We will use an example to describe the variations and explain our solution.

There are diamonds and CZís which have girdles which have a conical format; i.e. opposite sides of the diamondís girdle are not parallel (as shown in figure 1 (a, b) from a Helium scan which has a 4į inclination from the vertical).

Figure 1. Model of a CZ created with Helium. Note the girdleís deviation from vertical in the magnified image.

a) Side view of the CZ model.

b) Magnified side view of the CZ model.

When we manually measure the diameter (with an instrument like a Leveridge gauge, micrometer etc) the orientation or direction of the measurement of diameter can be influenced by the girdle surface. This can lead even experienced experts to make an error.

If the device uses a hanging approach, such as the when the diamond is suspended between two prongs or jaws, then figure 2 shows how the instrument will usually clutch the diamond in such way that one part of girdle surface will be snug against a claw, while the other side will touch only one edge.

Figure 2. Manually measuring diameter with a measuring instrument can result in the measurement of a shorter distance because the instruments jaws can align themselves with the girdle plane which may not be vertical. The blue line demonstrates the mistaken diameter measurement.

a) Side view of the CZ model.

b) Side view of the CZ model with two blown up areas.

Even when we place the diamond table down in a Leveridge gauge, the stone can move ever so slightly, so that the diamondís table is no longer resting flat on the instrument. The result is a shorter measurement.

The Helium system measures the modelís diameter as a distance between two parallel vertical planes, placed perpendicularly to the table plane, as close to each other as possible. This could be likened to a more correct manual measurement; the diamond is held down flat in a Leveridge gauge by applying pressure with ones finger on the culet.

Figure 3. Measurement of diameter by the Helium system shows the distance between vertical planes (red lines) that determines the diameter. The blue line demonstrates the diameter is 0,011 greater than the likely manual result.

a) Side view of the CZ model.

Thus, the manual measured diameter (figure 2), can differ from the value of the diameter measured by Helium. But the Helium measurement is the same as a manual measurement using the correct technique. The difference between values in this actual example* amounts to 11 microns or 0,011mm.

*CZ of 0,5 ct, average diameter 5,06 mm, angle of girdle tilt is about 4į.

Calculation of the report parameters