Source : Webster's Revised Unabridged Dictionary (1913)

Pyrochlore \Pyr"o*chlore\, n. [Pyro- + Gr. ? pale green.] (Min.)
   A niobate of calcium, cerium, and other bases, occurring
   usually in octahedrons of a yellowish or brownish color and
   resinous luster; -- so called from its becoming grass-green
   on being subjected to heat under the blowpipe.