Quartz is one of the most important minerals on earth and makes up one of the most popular gemstone groups in the world of colored stones. It is the second most abundant mineral found in Earth’s continental crust, second only to the feldspars. The name ‘quartz’ is thought to be derived from the German word ‘quarz’, which likely originated from the Slavic and Polish words meaning ‘hard’. The name is descriptive in regard to quartz being the definitive mineral that measures 7 on the Mohs scale of hardness. Other gemstones are often compared to quartz when it comes to classifying them as being hard, soft or durable.