NNP

Matrix.  The element which gives form to something else; as a die from which a piece is struck. In striking a coin or medal, a matrix is a working die; it is negative (concave) for striking positive pieces. The matrix for striking can be made in any of three ways:  1) from a patrix, hub, or master die; (2) cut from a dieshell on a die-cutting pantograph; or (3) handcut engraving.

In diesinking a matrix is the pattern for a letter punch, called a matrix plate. Diesinkers, particularly early ones, made their own letter puncheons, and often, their own matrices. The matrix plate would be formed of hardened steel and an iron punch would be softened, pressed into the matrix plate, then it would be hardened by quenching. It could then be used to punch letters into a die.

In electroforming a matrix is also considered a pattern, the mold from which an electrogalvanic cast is made; it is wired as the cathode to form the cast by electrodeposition. The resulting galvano reproduces the matrix exactly. This matrix is also called core pattern, mandrel, or (in England) a former.

In bas-relief the matrix is the background from which the relief is formed; thus the matrix can be considered the metal (or other composition) from which the relief emanates on a cast or struck piece. In openwork it is the matrix that is removed to form open space.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators

COMPILED AND WRITTEN BY D. WAYNE JOHNSON