Feldspars are complicate both in structure and in composition. Perthite is a representative mineral for the situation. Read information about perthite in the textbook and consider the following questions (a brief definition of antiperthite can be found on this web site):

This image (sample) shows a perthite rather than an antiperthite. Is there a convenient way to tell which one is it on a hand specimen scale?

In the course of Geology 101, this specimen is called "orthoclase". Consider the level of the course, is it a good name for this mineral? Why doesn't the Geology Department use true orthoclase for the course?

The part of red square in the top image is enlarged in the lower image through a binocular microscope. The width of the lower image is 3 mm. Describe the perthite shown in this image. Does it show any feature not obvious in the un-magnified image?