Color in Minerals

Minerals are made of atoms of elements that are energetically bonded to each other. Atoms have no inherent color, so why are there so many different colors of minerals?
 
"What we see as color is the result of our brain's interpretation of the dominant wavelength of light. Minerals are colored because certain wavelengths of incident light are absorbed, and the color we perceive is produced by the remaining wavelengths that were not absorbed. Some minerals are colorless. This means that none of the incident light has been absorbed."
     *Read the full article from Eastern New Mexico University HERE.

The most common sources of color in minerals are:
  • The essential composition of the mineral (example, celestite) and its structure 
  • The presence of trace elements in a mineral (example, Fe in quartz  amethyst or citrine) 
  • The presence of small amounts of another mineral in a mineral (example, hematite in feldspar  pink to orangey tones)
  • Physical defects in the crystal structure of the mineral create color centers.
  • Physical structures within the overall mineral (like closely spaced compositional intergrowths ( in labradorite))
 Note that the techniques required to correctly identify the source of color in a particular mineral and its composition or structure are high tech and extremely costly. Recent advances in mineralogical analysis have resulted in greater understanding of the origin of color in minerals, often unseating earlier educated guesses.