How quartz looks depends on the variety. Pure quartz is a clear, colorless crystal. Citrine quartz is a yellow or brown colored, clear crystal that looks like yellow topaz. Rose quartz is light pink to deep red, and usually cloudy, which makes it less popular. Amethyst is a variety of quartz that comes in many shades of purple. Smoky quartz is usually clear, and can be anywhere from light gray to almost pure black. Milk quartz is the most common variety, and takes it’s name from the white, opaque color of the stone.