Defects Terminology
There are many defects that appear on ancient coins. Here is a list of those frequently encountered. |
| Term |
Meaning |
| Broken
(Chipped) Patina |
The
patina has been damaged in areas and is no longer complete. |
| Cleaned |
Chemically
cleaned, removing the natural patina. Sometimes necessary, never desirable. |
| Clipped |
Material was
surreptitiously removed from the edge of the coin by clipping or shaving, reducing its
diameter - sometimes to the point of removing part of the design. |
| Corrosion |
Chemical
attack causing loss of detail over the area affected. |
Countermark
(Banker's Mark) |
A stamp
applied to the coin effacing part of its design. This was often done as a guarantee the
coin had been inspected by someone - a banker or government official. |
| Crystallization |
A condition
affecting silver coins in which the surface takes on a grainy crystalline appearance.
Caused by long term metallurgical changes and may result in brittleness. |
| Die flaw |
The die was
cracked or broken, leaving a raised area on the coin. |
| Double
Strike |
The coin was
struck twice with a die shift resulting in a doubled design. Striking variations such as
this are considered defects in ancient coins, not valuable errors. |
Encrustation
(Adhesions) |
Area(s) of
material adhering to the surface of the coin, outside the patina, that are difficult
to remove. They frequently appear to form a "crust" over part of the design. |
| Flan crack |
A crack in
the coin, usually caused during striking. The flan may not have been hot enough. |
| Flan chip |
A small area
broken away from the coin. |
| Flat or
Dead spot |
An area in
the center of the coin that is not fully struck. This is commonly found in large thin
coins where there was not enough metal in the flan to fill the design in the dies. |
| Flatness |
An area of
the coin that is not fully struck due to an irregular or incomplete strike. |
| Fourre |
A false, or
plated, coin. Ancient counterfeits were made by striking coins with base metal cores and a
thin skin of precious metal. |
| Graffiti |
Letters and
other designs intentionally scratched into the coin's surface. |
| Granular
surface |
Due to the
effects of corrosion, the coin's surface is no longer smooth but has been roughened where
material was leached away. |
| Heavy or
Thick Patina |
The patina is
so heavy that it begins to obscure detail and degrade the coin's appearance. |
| Holed |
A hole has
been drilled through the coin, usually to wear it as a pendant. |
| Horn Silver |
Silver
Chloride. Sometimes part of a coin will have combined with chlorine to form AgCl without
separating from the rest of the coin. It appears as a protruding grayish mass. |
| Irregular
Flan |
The coin's
edges are irregular due to uneven spread of the flan upon striking. |
| Lamination |
An area where
a thin layer of the metal separated from the flan during striking. |
| Mottled
Patina |
The patina is
covered with patches or spots of an alternating color. If this is severe, the coin
may seem to have the "measles." |
| Mounting |
The coin has
been, or is still, mounted for use as jewelry. |
| Nick |
A short cut
or groove in the edge or surface of a coin. |
| Off Center |
The device is
not centered on the flan, so part of the design is missing. Ancient coins were seldom
perfectly centered, so noting this usually means twenty percent or more. |
| Overstruck |
The coin was
not struck on a new flan, but on all or part of an older coin. |
| Pitting |
Indentations
caused by corrosion. May vary in diameter from small to large and from slight to severe in
depth. |
| Porosity |
Area(s) of
pores formed in the metal by leaching of alloyed material due to corrosive action. Large
pores appear similar to pits but are of different origin. |
| Rough |
The coin's
surface is rougher than normal for its preservation grade. |
| Scratch |
A long
indentation of slight depth and width. Normally caused by rough handling. |
| Short or
Small Flan |
The coin's
blank was not large enough to receive the entire design, part of which is off flan. |
| Smoothing |
Abrading or
cutting the surface of a coin to remove roughness, usually in the fields. |
| Test Cut |
A cut into
the edge or surface, to detect a plated counterfeit (see Fourre) |
| Tooling |
Recutting the
coin's design to improve on its actual condition. Very common on large Roman bronzes. |
| Unpatinated |
A bronze or
brass coin without a patina, usually due to a cleaning process (though some coins don't
form a patina for natural reasons). |
| Weak Strike |
The design
lacks detail because the coin was not struck hard enough. |
| Worn Die |
The design
lacks detail because the die was worn out. Very common on the reverse of Roman coins. |
