Tourmaline,

ring silicate whose color palette is extremely variable and can even vary along the longitudinal axis of a single crystal (e.g. watermelon tourmaline). Tourmaline is used as a gemstone.

Quartz,

second most common mineral of the earth's crust. Pure it is completely transparent and colorless and is called "rock crystal". Due to the inclusion of colored minerals or other causes, quartz can be colored differently. Yellow to orange brown quartz is called "citrine", violet as "amethyst", pink as "rose quartz", etc.