Diamond Polariscope portable shows if a stone is double or single refractive through a pair of polarized lenses.
This is an extraordinarily valuable field identifying instrument.
The polariscope is perfect for differentiating red spinels from red rubies, also tourmalines from glass, natural aquamarines from its the most common imitation – synthetic spinels, diamonds from synthetic moissanites, rock crystals from glass.
The polariscope is composed of a battery and two polarizing filters. One is located in the upper part of the instrument, the second in its lower part just above the battery.
Foils (polarising filters) are rotatable 360 degrees. The test method sees that the two filters must be set in the crossed position so that no light is seen before testing.
Then the examined gemstone is put between the filters. If this stone remains dark when being rotated 360 degrees in all directions, then it is amorphous or cubic.
If the stone becomes light and dark then it crystallized in other crystal system.
Insert an unknown colourless faceted stone between the crossed polarizers. The stone is rotated and becomes light and dark. It cannot be a diamond because a diamond is cubic and therefore it should remain dark, but it could be a moissanite crystallizing in the hexagonal crystal system and therefore it must go dark and light.