The atomic structure of an object will determine how it handles the light. Diamond in its purest form, 100% crystallized carbon atoms, will be colorless. Most diamonds will pickup other atoms in the crystallization process and as a result, will display various colors. These atoms or impurities re-radiate certain light components, which produces the visible colors that we observe, as in the example of the apple. Although research continues, we still do not fully understand the effects that foreign elements have on diamond color. Some elements that have been confirmed as affecting color include nitrogen and boron. As few as 100 atoms of nitrogen in every one million carbon atoms, absorb the blue and violet end of the spectrum and as a result, yellow is returned to our eyes. Boron does the opposite, returning blue back to our eyes. Green diamonds get their color from exposure to natural radiation, having been located close to radioactive rock during the crystallization process. This radiation does not introduce foreign atoms (or radioactivity) into the diamond, but actually changes the diamond crystal structurally. So structural changes or additional impurity atoms (other than carbon) can both affect color.