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Webster 1913 Edition

Noun.

[Named after Thomas

Jefferson

(Min.)

A variety of pyroxene of olive-green color passing into brown. It contains zinc.

Noun.

A mineral occurring in crystalline masses, of a dark olive green color passing into brown, found imbedded in Franklinite and garnet, in New Jersey.

jeffersonite ‎(uncountable)

(mineralogy) A variety of pyroxene of olive-green color passing into brown. It contains zinc.