Cut a small piece of rock (oriented or non-oriented) from a rock specimen with a slicer. Smooth one side of the stone on the grinder. Glue this plane to the middle of a glass slide (25 mm×50 mm in size and about 1 mm in thickness) with Canadian glue. Grind the other side to a thickness of 0.03 mm and stick the cover glass on the rock with Canadian glue (the size of the cover glass is15 mm×15 mm ~ 20 mm× 20 mm and the thickness is 0. 1 ~ 0.2mm). Therefore, rock flakes are composed of thin mineral flakes, glass carrier flakes and cover glass flakes (Figure 3-9). There is a thin layer of Canadian gum above and below the ore slice.
Figure 3-9 Rock Slice Longitudinal Section
Use emery when grinding rock slices. No matter how fine emery is, there will always be micro-grooves on the surface of the chip. Therefore, the surface of the slice is not absolutely smooth.
For some identification needs, such as observing cleavage joints of feldspar, staining thin slices or doing electron probe analysis, some ore slices are not covered with glass sheets or some are not covered with glass sheets. When grinding loose rocks into thin slices, soak them in Canadian gum and boil them before grinding them.
Study Guide
Compare with books, understand each part of polarizing microscope and find out its function. Repeatedly practice loading and unloading lenses, adjusting lighting, adjusting focal length, and correcting the center until you are proficient. Practice and learn how to measure the diameter of visual field, check the crosshair of eyepiece and correct polarizer.
Review thinking questions
1. What is the main part of the polarizing microscope?
2. What's the difference between polarizing microscope and ordinary biological microscope? Why are there these differences?
3. When calibrating the center, twist the calibration screw. Why can point A only move to the eccentric center O' but not to the crosshair center O?
4. How can I quickly adjust the lighting, focal length and center?