The optical characteristics of materials can be effectively studied with the use of a polarizing microscope. But it's crucial to be mindful of the possibility of artifacts, which are characteristics that appear under a microscope but are absent from the material itself. Among the typical artifacts observed in the polarizing microscope are:

 

  • Stress birefringence: The source of this kind of birefringence is stress within the sample. Either band of extinction or interference colors can be seen. Excessive cutting or polishing of samples frequently results in stress birefringence.

 

  • Birefringence caused by the mounting medium: This kind of birefringence arises from the birefringence of the mounting medium. Either band of extinction or interference colors can be seen. Using a mounting medium with a low birefringence will reduce the mounting medium's birefringence.

 

  • Coverslip birefringence: This kind of birefringence results from the coverslip's birefringence. Either band of extinction or interference colors can be seen. It is possible to reduce coverslip birefringence by utilizing low-birefringence coverslips.

 

  • Artifacts resulting from crystallization of the mounting media surrounding the sample: these can happen. They may take the shape of plates, rods, or needles. Slow-to-crystallize mounting media can help reduce artifacts caused by crystallization.

 

  • Air bubbles: Within the field of view, air bubbles can manifest as black circles or crescents. Air that has been trapped between the sample and the coverslip may be the source of them. Using a rough tool, gently press on the coverslip to remove air bubbles.

 

It is possible to confuse artifacts for actual sample characteristics and draw the wrong conclusions as a result. For instance, birefringence resulting from stress may be confused with birefringence resulting from the presence of a certain mineral. If you notice artifacts in your photos, it can indicate that the microscope has a problem. Examples of such problems include a birefringent coverslip or a dirty objective lens.