Gems are minerals or rocks that must be polished or cut to reveal their beauty. Examples of gems are diamonds and rubies. Gemstones, on the other hand, are minerals or rocks that do not require cutting or polishing. Examples of gemstones are opals and pearls.
Gemstones were traditionally classified as "precious" or "semiprecious" based on the three factors of beauty, rarity and hardness. That classification system has become less popular over time due to the subjectivity of beauty. In the 1940s and 1950s, the Gemological Institute of America developed the GIA International Diamond Grading System to evaluate that particular gem more objectively.
Gemology was taught for the first time in the United States in 1909. It was a course for geology students taught by Dr. G. Montague Butler at the Colorado School of Mines.
Several organizations and educational institutions in the United States offer training in gemology. One of the most prestigious professional credentials in the industry is the Gemological Institute of America's Graduate Gemologist Diploma.
Quartz has been used to make jewelry for the last 4,000 years. But even before that, humans were making good use of the gemstone. Quartz was carved into spear points for hunting and fighting.