Source : Webster's Revised Unabridged Dictionary (1913)

Lumachel \Lu"ma*chel\, Lumachella \Lu`ma*chel"la\, n. [F.
   lumachelle, It. lumachella, fr. lamachella a little snail,
   dim. of lumaca a snail, fr. L. limax, -acis.] (Min.)
   A grayish brown limestone, containing fossil shells, which
   reflect a beautiful play of colors. It is also called {fire
   marble}, from its fiery reflections.