NNP

Hollow.  Not solid; a medallic item with depressed area on the reverse concordant to bold relief on the obverse. Also medallic items which have not been filled with metal (as drop-in lead) before a backplate or reverse shell was applied. Medallic items are made hollow for the obvious reason to reduce weight.

Hollow medals are two-sided medallic items made of two separate shells joined together at the edge without a drop- in. They are easy to detect because of their obvious light weight. Hollow medals are often made to be worn and can be fairly large size – three and four-inch diameter and more – without the heavy weight of a solid medal.

Cast medallic pieces are sometimes called cast hollow when the depressed area on the back is visible; this term is somewhat of a carryover from describing statues and statuettes (which are almost always hollow). Cast hollow plaques, shells and such can be made by any casting method, but particularly by shell mold. Cast double medallic items have two cast hollow plates which are usually soldered together with a metal drop-in.  See cast, casting.

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