Review of the drawing of crystal forms and its procedure.

From the later half of the nineteenth century to the early twentieth century, the progress of mineralogy had brought about more complete descriptions of many crystalline objects. During the period, endeavors to express three-dimentional crystal forms as precice as possible were begun by use of projections on a plane. Since then, the endeavors have developed a uniqe method as “the drawing of crystal forms” based on “the clinograhic projection” which prescribes a certain fixed relation between view point (the direction to project) and crystal axes. This drawing can be made with Wulff's net construction of an axial cross, or the calculation of zone axes (Parker's method), etc. Although crystal drwings with this method make it possible to understand three-dimensional crystal forms at a glance, the method has been less frequently used because it requires annoying procedures or troublesome calculations. Recently, such obstacles are ovrcome with the help of personal computer or handy calculater, and crystaldrawings can be more easily done. This paper reviews “the drawing of crystal forms” and explains the concrete procedure of drawing of crystal and twin forms.