Definition of crystalline

The word "crystalline" derives from the Greek word "krystallos" meaning "ice-like." This term was coined by Theophrastus, a Greek philosopher, in the 4th century BC. Interestingly, the ancient Greeks noticed that certain minerals such as quartz resembled ice, both in appearance and when they slimed when hit, giving them the name "krystallos." Later, during the Renaissance, when investigations into the nature of minerals began to intensify, the word "crystalline" came into vogue again. It was primarily associated with minerals that exhibited a fixed, regular shape due to the arrangement of their atoms in a repeating pattern. This repeating pattern is known as a crystal structure, which gives these materials their characteristic crystal shape. Today, the term "crystalline" is not limited solely to minerals, but can be used to describe any substance that has a crystal structure, including certain types of organic compounds and some glasses.