Paper with dot Table of Content

Download paper: paperChecked_1.jpg When a gemstone is placed table down over a dot or line on a piece of paper, it may or may not be possible to see it through the pavilion. If the dot is visible then that indicates that the gemstone will show a see through or window effect when seen from the pavilion. This is shown in the subsequent examples.

Brilliant Natural on paper with dot Table of Content

Download scenario: brilliant_natural_dot1.zip In this case the diamonds proportions (57% table Tolkowsky) does not allow the observer to see out the table of the diamond. That is a desirable thing.

Brilliant CZ on paper with dot Table of Content

Download scenario: brilliant_cz_dot1.zip In this case a cubic zirconia (CZ) round brilliant allows the observer to see the spot, indicating that the stone will have a window. The reason this happens in CZ is that the refractive index is lower at 2.174 compared to diamond at 2.418.

Brilliant Natural with pavilion angle 38o on paper with dot Table of Content

Download scenario: brilliant_natural_pav38_dot1.zip In this case simply by reducing the pavilion angle from 40.75o to 38.0o the dot becomes visible. The ray trace image below helps to explain why.

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