How to recognize a diamond
The best known method is certainly the "proof of the glass": if the diamond is mounted on a ring it is sufficient to rub on a glass and we will get a fine scratch on the glass and no damage to the diamond.
Let's add a method less known, but certainly original.
It is necessary to highlight that this assessment is well suited not only for diamonds embedded and cut into brilliant.
As you can see, if the diamond has been cut respecting the "ideal measures", all the light rays that strike the upper part (table), penetrate the gem and them escape from the same part.
And here is the method that allows us to determine whether a brilliant cut diamond is a real diamond and its proporsioni cutting are ideal.i.
Since all of the light that penetrates from the part of the "table" comes out exclusively by the table itself, also the image of the point will penetrate the gem to exit from the same side, upwards.
Consequently, observing the brilliant from his back, the point will be completely invisible..
The spire of the gem we appear completely non-transparent, as if it were composed of polished steel.
If the point were to be visible, such as observing it through a magnifying glass, we would be facing an artifact or a stone which is not a diamond, or in front of a brilliant cut diamond without compliance with the "porporsioni ideal".