History of crystal growth
The vast majority of work done on crystal growth has been concerned with practical methods rather than with theoretical analyses. The first synthetic gemstones were made in the mid-1800s, and methods for making high-quality crystals of various materials have been developed over the course of the past century. Since the mid-1970s such crystals have been crucial to the semiconductor industry. Systematic studies of the symmetries of crystals with flat facets began in the 1700s, and the relationship to internal structure was confirmed by X-ray crystallography in the 1920s. The many different possible external forms of crystals have been noted in mineralogy since Greek times, but although classification schemes have been given, these forms have apparently still not been studied in a particularly systematic way.