(computing, programming) The property of being falsy, i.e. evaluating to false in a Boolean context.

(mineralogy) Any of the rock-forming minerals pyroxene, amphibole, and mica.

(crystallography) Of or pertaining to morphotropism / Describing a phase transition due to a change in composition

(mineralogy) A compact granular cryptocrystalline mineral of a dull grayish or greenish white color. It is a hydrous alkaline silicate, and is derived from the alteration of other minerals, such as...