The Crystallography and Forms of Gemstones

When new material is introduced in later assignments you will have had a background for it in previous assignments. In this one, however, you will be confronted with a wealth of information for which you have had no prior background. How gemstones are formed in nature and their structure and shapes are exceedingly important subjects about which the gemologist must have a basic understanding. This forms essential groundwork for the understanding of the relationship between the internal structure of the gemstone and its properties. This assignment, of course is not one that needs to be memorized, but it is one in which a general understanding of basic principles is important. Most people find this subject matter fascinating, whether they have any direct application for the information or not. The study of how materials form in nature into the minerals we see and the growth of crystals are subjects that still retain many elements of mystery. Many pursue these subjects as a hobby because they find the whole field fascinating.


The things we see around us may be divided into two very broad classes:

The organic materials of course, are included in the plant and animal kingdoms, and the inorganic materials are confined to the mineral kingdom. Among gemstones we distinguish between those resulting from the activities of plants or animals (those of organic origin) and those of inorganic origin (rocks and minerals). Those of organic origin include pearl, coral, amber and jet. All other gem substances are either minerals or other materials of inorganic origin.