NNP

Fishtail.  Unsightly marks on a patinated surface; dark streaks vaguely resembling the tail of a fish. A fishtail surface is a patina anomaly. Also called wipe marks.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators

COMPILED AND WRITTEN BY D. WAYNE JOHNSON

Roger W. Burdette, Editor