Two blue tourmalines.

Both of these tourmalines are blue because they transmit light in the 500 nm region.  The elbaite from Salinas, Minas Gerais, Brazil, owes its color to Fe2+ whereas the elbaite from Sao Jose de Batalha, Paraíba, Brazil, owes its color to Cu2+.  Although there are strinking differences in the optical absorption spectra of these minerals, because they occur predominantly in the near-infrared region of the spectrum, they have little effect upon the color of the minerals.

Back to the Spectra page

Back to the Mineralogy page