Quartz crystals are naturally occurring minerals made of silicon and oxygen. They are one of the most abundant minerals on Earth and can be found in various colors, including clear, purple, and smoky. Quartz is known for its hardness and durability, making it a popular choice for jewelry and decorative items. These crystals form in a variety of geological environments, often in igneous and metamorphic rocks. Silica is the primary component of quartz, and its unique structure allows it to vibrate at specific frequencies, which is why it is also used in electronic devices like watches and computers.