Polymnite

• (n.) A stone marked with dendrites and black lines, and so disposed as to represent rivers, marshes, etc.
Found on http://thinkexist.com/dictionary/meaning/polymnite/

Polymnite

Pol'ym·nite noun [ Greek ... full of moss; poly`s much + ... moss.] (Min.) A stone marked with dendrites and black lines, and so disposed as to represent rivers, marshes, etc.
Found on http://www.encyclo.co.uk/webster/P/122
No exact match found