Electron Microprobe and Optical Absorption Study of Colored Kyanites

Science  17 Nov 1967:
Vol. 158, Issue 3803, pp. 915-917
DOI: 10.1126/science.158.3803.915


The characteristic blue color of the mineral kyanite is shown to be caused by traces of Ti+++ in the range of a few parts per million. Evidence from the intensity and position of optical absorption bands indicates that the unusually intense color probably arises from electron delocalization into narrow d-bands.