Pronunciation: (al"u-kru-mat'ik, -krō-), [key]
1. Physical Chem.pertaining to or having photochemical properties resulting from an impurity or from exposure to radiation.
2. Mineral.(of a mineral) having no color in itself but bearing colored impurities. Cf. idiochromatic.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.