Industry WIKI

A pattern coin is a coin which has not been approved for release but is produced to evaluate a proposed coin design. They are often off-metal strike (using metals of lower value to test out the dies), to proof standard or piedforts. Many coin collectors collect and study pattern coins because of their historical importance. Many of the world's most valuable coins are pattern coins; nearl

Proof coinage refers to special early samples of a coin issue, historically made for checking the dies (as in demonstrating that something is true) and for archival purposes. In modern times, proofs are often struck in greater numbers, especially for coin collectors (numismatists). Nearly all countries have issued proof coinage.

The Standard Catalog of World Coins is a series of numismatic catalogs, commonly known as the Krause catalogs. They are published by Krause Publications, a division of Active Interest Media.

Toning on a coin is the change of colour brought about through oxidization, which forms a thin layer of tarnish on the metal's surface, typically as a result of interactions and chemical reactions with sulfur-containing compounds in the environment. Coin toning can vary in aesthetics, and thus can alternately add or detract from a coin's value. Coins with unusual toning colours or patter