The role of contaminant diffusion purple quartz, otherwise known as amethyst, is commonly known for its occurrence as clusters of gemmy crystals that grow on the walls of fluid-filled fractures and vugs in hydrothermal ...

Gemmy hydrothermal quartz crystals typically exhibit each of their six prism and six rhombohedral crystal faces. However, discerning which of the crystal faces were actively growing at any given time during construction ...