Polariscopes facilitate the rapid detection of common gemstone imitations, such as glasses or synthetic spinels. To examine gemstones and ornamental stones – but also syntheses or imitations – these are positioned on the rotating glass plate above the polarizer. The materials to be examined are located between the polarizer and the analyzer and can be moved with the glass plate. The lighting comes from below and the materials are viewed from above. The stone lying on the polarizer or held between the filters is rotated.
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Tips for working with the polariscope
When working with the polariscope, the best results are achieved if the stones to be examined are additionally embedded in glass vessels with immersion media. If the polarizer and analyzer are rotated exactly 90 ° against each other for the dark position, the background of the stones is black.
If the stone in the dark position of the polariscope shows four times bright and four times dark when rotated 360 °, it is identified as an anisotropic stone. In this case, it could be a red gem such as ruby or tourmaline. In the case of a ruby, however, it must be taken into account that a synthetic ruby can also be present. If dark bars move through the stone when turning, this speaks for simple glass.
The inner structure is responsible for the different modes of appearance. Natural or synthetic non-organic materials have a regulated internal structure on an atomic scale, which is known as the crystal lattice or crystal structure. Glasses, on the other hand, are largely disordered, they are amorphous. In the case of transparent materials, such as precious stones and other minerals, a distinction is made between so-called single-refractive (isotropic) and double-refractive (anisotropic) materials and special cases.
There are many other examination methods with the polariscope and a wide variety of appearances with which the inner crystal lattices or crystal structures can be observed. We have compiled a large selection of relevant specialist information with many interesting detailed photos and descriptions of the basic examination methods in a free white paper. This specialist publication was produced in collaboration with Prof. Dr. Jochen Schlueter wrote. He is a qualified mineralogist and is responsible for the permanent collection of the Mineralogical Museum in Hamburg.
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Here you can order the whitepaper “Polariskopie” free of charge, in which many examination possibilities with the polariscope are described. Simply enter your contact details here and we will send you our detailed whitepaper as a PDF by email.