The first examination of the mineral section should be made with the one inch objective where both polarizer and analyzer are being swung out of the axis of the petrographic polarizing microscope.

 

            As expected, it will be seen that the thin section being evaluated under the polarizing microscope is made up of several minerals, some are transparent while other are opaque. The first evaluation should confine to the study of those minerals that transmit a certain amount of light or transparent minerals. The method of examination of opaque mineral will be discussed later. The characters discussed in this section include color, form, cleavage, refractive index, alteration, inclusions, and zoning.