Snellius Minerals LLC Isotropic versus Anisotropic Kit

Описание: This video explores the difference between isotropic and anisotropic materials and how a polariscope can be used to distinguish them. We first examine how light travels differently through fluorite and calcite crystals under normal lighting conditions. We then learn a bit more about how calcite interacts with light by adding a linear polarizer to our view. Our next experiment uses a polariscope to examine spinel and tourmaline with transmitted plane polarized light. This setup allows us to determine if either of these minerals are pleochroic. The pleochroism displayed by the tourmaline confirms that it is anisotropic, however the lack of pleochroism displayed by the spinel is not sufficient to determine that spinel is isotropic. This experiment in plane polarized light is followed by using our polariscope to examining our spinel and tourmaline with crossed polarizers. In this setup we can observe that our tourmaline crystal displays the extinction and transmission of light with rotation, additional confirmation that the tourmaline is indeed anisotropic. The spinel remains extinct with crossed polarizers, proving that the spinel is isotropic. In our final experiment we examine the fluorite and calcite crystals from earlier using our polariscope and confirm that calcite is anisotropic, whereas fluorite is isotropic.