The Collaborative International Dictionary of English v.0.48:

Ripidolite \Ri*pid"o*lite\, n. [Gr. ???. ???. fan + -lite.]
   (Min.)
   A translucent mineral of a green color and micaceous
   structure, belonging to the chlorite group; a hydrous
   silicate of alumina, magnesia, and iron; -- called also
   clinochlore.
   [1913 Webster]