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Unusual Shape

Unusual Shape.  Any shape of a numismatic or medallic item other than circular. Designers have employed every popular shape in creating distinctive coins and medals, including: ovals, triangles, rectangles, pentagons, octagons, stars, rosettes, diamonds, hearts, keystones, bells, shields, and a variety of other shapes, for medals and tokens more so perhaps than coins. All shapes require distinctive blanking and trimming to create their required shape. (Cast pieces do not require trimming because they can be molded to shape.) Some large round medals can be turned to a circular shape on a lathe as trimming – all other struck pieces require special blanking and trimming tooling to produce their shape.

The reasons for choosing a shape other than round are varied. Odd-shaped coins

in India aid the large number of blind people there. Unusual shaped tokens are struck to give them distinction from one another, to help in sorting large quantities when mixed with other tokens. For medals the most important reason is symbolism; a shape is chosen because it is symbolic of the subject.

Unusual-shaped coins.  Only the smallest number of  coins are not round; those

which are, for the most part, are either square, scalloped or some geometric shape. Most often odd-shaped coins have a number of sides from five to twenty (the larger the number of sides the closer the piece looks circular). Like circular coins, unusual shaped pieces are stamped one at a time inside a collar; the collar must be specially prepared to the shape of the intended piece.

With the increasing popularity of bimetalic coins, the creation of blanks with

a large center aperture, are required. Such ring blanks are considered an unusual shape because of the technology required is similar to creating unusual-shaped blanks.

Unusual shape and manufacture of tokens.  Some odd- shaped diestruck items are made from strip stock (often with a center hole). These are struck with the design, then the hole is pierced, then the odd-shaped item is blanked from the strip. This stamping, piercing and blanking is done all at once (with one cycle of the press) on three tokens at three different positions. This is accomplished with combination dies where the strip advances a prescribed distance, for the next operation to be performed.

This technique does create somewhat more scrap than blanking individual circular discs first but the process is accomplished quicker at a lower total cost. Many tokens, particularly transportation tokens, are struck in this manner.

Medallic art ideal for unusual shapes.  Far higher percentage of medals are made in unusual shapes than coins. This can be attributed to several factors: medals do not need to circulate, they do not need to fit vending machines, and they can be made more beautiful. Medals, plaques and medallic objects are often of such shape that its configuration has a symbolic meaning for the theme of the object. The chart gives an indication of the wide variety of shapes that have been created for medallic items.

For those medallic items that are cast, the shape is of less concern than for a

struck object. Creating a blank, specially shaped dies and trimming tools contribute to the requirements of the struck piece. A cast piece can be of any convenient shape with its design and configuration created in one casting.

Beautifying a shape.  A basic shape can be modified in a number of ways by

designers, for medals more so than coins. Most common methods are rounding the corners or curving a straight edge. These are done to give the final shape a more attractive, more appealing appearance. The box contains a list of modified variations.

           How Artists Beautify a Shape                   


       Rounding the top.                                  

       Rounding the corners.                              

       Notching into a basic shape.                      

       Clipping the corners (centered).                  

       Pointing the bottom (as a shield).                 

       Bending or curving a straight edge.                

       Adding a base or molding to the piece.             

       Adding small projection(s) beyond the outline      

           of the shape (called hyperdimensional).        

How unusual shapes are made.  For diestruck pieces a blank is required

roughly the shape of the intended piece. After it is struck it must then be trimmed with a trimming tool. If there is no tool on hand at the plant where it is made, then the tooling must be created. Such special blanking and trimming tools are made by a tool and diemaker  (see tool and diework).

Quantities to be struck are important. Less than fifty, say, could be trimmed by hand, by manually cutting to shape by jigsaw. For most production runs, however, mechanical trimming tools are needed, with a punch and plate cut in drill rod and steel plate to the specifications of the final configuration of the intended shape.

While an unusual shape can be struck on a round blank (where the intended shape fits within the circular diameter) this is somewhat wasteful because greater scrap is generated. Usually this is only done where time is a factor, or perhaps an oversupply of such blanks are on hand; with large production runs, specifically, the proper tooling is created.

Infrequently a trimming tool is used as a blanker to cut from strip stock the odd-

shaped blank. After the piece is struck (with open face dies and the resulting flash), the same tool is employed to trim the fully struck up piece to its final shape.

Cast pieces need no trimming tool, as the item can be cast to the intended finished shape.

Symbolism in shapes.  All medallic items, even circular can have some symbolism for their shape, unusual shapes particularly so. The meaning of having a specific number of sides is obvious. A Christian medal can be shaped like a cross, a Jewish medal as a pentacle, a heart association, obviously, shaped like a heart. An extreme example, but somewhat subtle, was the New York Obstetrical Society Centennial Medal of 1963 shaped like a woman's uterus.

The designer is at liberty to chose a shape that is harmonious, significant or supporting the theme of the design. The shape adds interest and emphasis to the design. See also the entry symbols and symbolism.

Openwork shapes.  The center hole in some numismatic items often takes a shape other than round. For tokens, the shape of the center hole adds distinction that can help identify the token form all others of similar size and manufacture. Any openwork in a numismatic or medallic item is called pierced and is preformed by a piercing tool.

Cataloging shapes.  All shapes, other than round, of all numismatic and medallic items must, of course, be identified in cataloging. The chart lists the names for many such unusual shapes. These terms can be used for describing design elements appearing on the coin or medal as well as an item's physical shape. Since these terms are not in most people's everyday language it is certainly permissible to use the term and put its meaning in parenthesis following. The most overlooked element in cataloging are the projections beyond the original flan, all hyperdimensional elements must be identified.

Also all openwork, the hole or other aperture, must be described. It's location and shape should be mentioned, even if it is a center hole. The shape of the edge should also be mentioned and whether it was formed by jigsaw or by trimming dies.

See circular form, silhouette, blanking, trimming, jigsaw.


N19 {1993} Mackay. Shapes and Sizes, p 143-163.

[[Sidebar illustrated with SoM #129 dinosaur medals]]

How These Medals are Trimmed To Their Unusual Shapes.

THESE medals are not struck in collars (which are typically round or oval). So how are these unusual shapes formed? It is done with trimming dies that have to be machined (by a tool and die maker) to the intended shape that is desired – a different set of trimming dies for each shape.

            The obverse and reverse designs are struck on round blanks, somewhat oversize. The striking dies are open face dies and the use of these creates flash where the excess metal squeezes out between the dies around the edge of the blank. The multiple striking causes the flash to grow larger after each blow. But this flash is not a problem as it will be removed along with the dead metal from the unwanted portion of the blank.

            At least one side of an unusual shaped medal will have to have a rim. This is for the punch die (cut to the desired shape) to contact as it presses the entire medal through the trimming plate die which has an edge that is harder than the composition of the metal and cut to the shape wanted for the unusual shape of the medal. The punch die and trimming plate die are mounted in a die set that is placed in a press (perhaps the same 1,000-ton knuckle-joint or hydraulic press that struck the pieces).

            The clearance between the punch die and the trimming die is less than a thousandth of an inch. Under the edge of the trimming die is a slight bevel sloping away from the edge to allow the medal to fall through the trimming die as the punch pushes it through. There will be a burr edge on the last side of the medal to go through the trimming die (all shearing operations leave a minute trail of debris) but this is not a problem as the burr will be removed during the finishing step.

            If there are any nicks or burrs on the trimming die this will show up as striations on the edge of the medal. If there are no striations on the edge both the tool and die maker and the trimming press operator did their jobs well. Result:  a smooth-edge Unusual Shaped Medal!

Word List  #27

    Names of Some Unusual Coin and Medal Shapes 


    Aliform – wing-shaped.                     

    Annular – ring-shaped.                     

    Balanoid – acron-shaped.                   

    Bursiform – pouch or purse-shaped.         

    Campaniform – bell-shaped.                 

    Capitate – head-shaped.                    

    Clithridiate – key-hole-shaped.            

    Conchiform – shell-shaped.                 

    Cordiform – heart-shaped.                  

    Cornual – horn-shaped.                     

    Cricoid – ring-shaped.                     

    Cruciform – cross-shaped.                  

    Cuniform – wedge-shaped.                    

    Cupola – dome-shaped.                      

    Dendriform – tree-shaped.                  

    Dentiform – tooth-shaped.                  

    Dolioform – barrel-shaped.                 

    Ellipsoidal – oval-shaped.                 

    Flabellate – fan-shaped.                   

    Floriform – flower-shaped.                 

    Foliform – leaf-shaped.   

    free-form – without symmetric form.        

    Galeate – helmet-shaped.                   

    Globular – droplet-shaped or tear-shaped.  

    Handerchief corners – four corners folded  

                inward slightly (8 sided), also called

                clipped corners.     

    Hederiform – ivy-shaped.                   

    Hominiformn – human-shaped.                

    Hyoid – U-shaped.                          

    Hypsiloid – Greek letter upsilon-shaped.   

    Infundibular – funnel-shaped.              

    Keystone – four sided (wider at top) with  

                knotched top corners and sloping sides..            

    lenticular – lens-shaped.                  

    Libriform – book-shaped.    

    Lozenge – diamond-shped.             

    lunette – half round.                      

    Lunular – crescent-shaped.                 

    mandorla – almond-shaped.                  

    Navicular – boat-shaped.                   

    Nephroid – kidney-shaped.                  

    Nummiform – coin-shaped.                   

    Oculiform – eye-shaped.                    

    Omegoid – horseshoe or omega-shaped.       

    Oriform – mouth-shaped.                    

    Ovoid – egg-shaped.                        

    Palmate – hand-shaped.                     

    Pandurate – violin-shaped.                 

    Pediform – foot-shaped.                    

    Pentacle – six-pointed star shape.         

    Pentagonal – with five sides, corners.     

    Pinnate – feather-shaped.                  

    Pisciform – fish-shaped.                   

    Pyriform – pear-shaped.                    

    Reniform – kidney-shaped.                  

    Rhomboidal – diamond-shaped.               

    Sagittate – arrowhead-shaped.              

    Scalloped – with numerous wavy rounded edges.                         

    Scutiform – shield-shaped.                  

    scyphate – saucer-shaped.                  

    Sigmoid – S-shaped.                        

    Stellate – star-shaped.                    

    Tau-shaped – like Greek letter tau.        

    Tombstone – rounded top, square bottom.    

    Toroid – donut or anchor-ring-shaped.      

    Triquetra – triangular.                    

    Urceoform – urn-shaped.                    

    Vesica piscis – vertical oval with two pointed ends.              

    volute – spiral-shaped.                     


    Names For Number of Sides (i.e. edges)      


    Three – Triangle.                          

    Four – Square.                             

    Five – Pentagon.                           

    Six – Hexagon.                             

    Seven – Heptagon.                          

    Eight – Octagon.                           

    Nine – Nonagon.                            

    Ten – Decagon.                             

    Twelve – Duodecagon.                       

    Twenty – Icosagon.                         

    Twenty-four – Tetraicosagon.               

CLASS 02.13

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators


Roger W. Burdette, Editor

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