Dendrite
Dendrite , noun
[Greek dendri`ths, fem. dendri^tis, of a tree, from de`ndron a tree: compare French dendrite.]
(Mineralogy) A stone or mineral on or in which are branching figures resembling shrubs or trees, produced by a foreign mineral, usually an oxide of manganese, as in the moss agate; also, a crystallized mineral having an arborescent form, e. g., gold or silver; an arborization.