With all hobbies, knowing the basics of how
things work are a must, a good starting point is the
Royal Australian Mint
making coins
A
Adjustment - Reduction of metal in a flan or blank to the specified
weight prior to striking, accomplished by filing down the face. Such file marks
often survived the coining process and are occasionally met with in coins, especially
of the eighteenth century.
Alignment - Alignment refers to the relative positioning of the obverse
and reverse designs of a coin or medal. Historically, until the last few centuries,
most coins were issued with the sides rotated 180 degrees (ie. the reverse is
upside down to the obverse). This is known as "Coin Alignment" or
"Coin Rotation" and continues to be observed by some coin issuing
nations such as the United States of America. However, most countries in recent
times now align obverse and reverse at 0 (or 360) degrees. This is known as
"Medal Alignment" or "Medal Rotation". See also the entry
for "upset" error coins
Alteration - The tampering with a feature of a coin's surface such as
the date, mintmark, etc. to give it the appearance of being another date, mintmark
or variety. An illegal practice
Altered date - refer to "Alteration" a good example is the 1930 penny.
Assay Piece - A sample coin included in an assay, supposedly picked at
random from production. Assay is the process of determining the purity of precious
metal, or the result of such a procedure.
B
Bitten edge - see Clipped planchet
Blakesley effect - A weakly-formed rim that occurs opposite the "clip"
on incomplete planchet coins
Blank - An unrimmed planchet or flan. Blanks are now stamped out by machine
whereas in early times they were customarily cut with special shears from a
cob of metal. Also see Planchet
Blob - An irregular raised feature anywhere on the surface of a coin.
It is either a rare form of cud where the die has chipped somewhere in the middle
(an effect called spalling) or, more commonly, the result of damage to the die
caused by some foreign object or hard impurity in a planchet
Broadstrike - A coin struck outside of the collar, resulting in the coin
"spreading" beyond its normal dimensions, with no edge reeding.
Broadstike (uncentred) - Is defined as a "broadstrike" that shows an
unequal thickness of spread around the circumference of the coin. Parts of the
field design should [usually] be absent, will appear at the outset to be a simple
less than 10% off-centre error.
Brockage - A coin with only one design, normal on one side and mirror
incuse on the other. This occurs when a coin previously struck adheres to the
die and strikes the next planchet to pass through the press.
C
Capped die - Is caused when a struck coin adheres to the upper
hammer die. Once the coin is adhered to the die face, the reverse of the struck
coin becomes the new die face. When the next planchet is fed into the collar
and the strike occurs, the reverse design of the adhered struck coin impresses
itself into the new planchet. This struck coin is a brockage strike. The coin
adhered to the upper die is known as a die cap.
Clash marks - see Clashed dies
Clashed Die(s) - The obverse and reverse dies, which have come together
in the striking process without a planchet in between. Coins produced thereafter
from such a pair of dies, usually show mirror-image traces of an obverse design
on the reverse, or, reverse design on the obverse.
Cleaned coin - While any coin subjected to a cleaning process could technically
be considered cleaned, this term most commonly refers to those, which have been
abrasively cleaned. This reduces the value of a coin, and in general, not the
preferred collectable coin. If you are considering cleaning a coin, Don't,
first seek as much advice as possible.
Clip - see Clipped planchet
Clipped coin - See clipping
Clipped planchet - An error coin struck from a planchet that has a piece
missing, usually caused by a malfunction in the blanking press. When a coin
is struck on a clipped planchet, the coin metal (metal flow) takes the path
of least resistance and tends to flow into the missing area of the planchet.
Various types can occur; see below for individual definitions.
----- Types of clips -----
1. Crescent clip - A major crescent-shaped clip that is the result of
an incomplete punch that breaks off along the punch line, or a loose blank repunched
off-centre on top of the strip
2. Curved clip - A blank punched out whilst overlapping
a previously punched area of the metal strip. Due to the metal strip not moving
forward enough between successive punchings
3. Multiple clips - a coin which exhibits two or more forms of clip.
4. Nip (clip)- A small portion of the coin
missing, when it is caught by the stroke of the Dies striking the next planchet,
some rim bruising maybe apparent as the coin is flipped by the action. Caused
when the coin is not ejected properly. (contentious, as some participants consider
this does not happen)
5. Ragged clip - rare - A blank punched from an unfinished
end of strip. Maybe thinner than usual but not necessarily.
6. Rim clip - A very small clip affecting the rim or border, these coins can have
a piece missing, and the type of clip being hard to detect. Or the edge of the coin can appear
complete, as the metal flow is force out to the collar die, but still showing
a weakness on the rim or border at the effected area and at times points opposite
the clip.
7. Straight clip - A blank punched from the periphery of the strip,
with the ends being the more common. Caused by the punching tool overlapping
the ends
Clipping - The practice of removing slivers of precious metal from the
edges of coins and passing the reduced-weight coin at original value, retaining
the slivers as profit. Graining and edge inscriptions were adopted to prevent
this.
Circulation strike - A regular issue coin, struck on regular planchets
by dies given normal preparation. These are the coins that the Mint places into
circulation.
Collar die - A restraining device used in the striking stage of coin
production, which encases the planchet and allows it to be struck centred by
both dies; in the case of errors, a fault in the collar will result in broadstruck
and off-centre errors.
Counterfeit/Forgery - An imitation of a numismatic item intended to deceive
and/or defraud.
Countermark - These are generally
applied singularly, and in most cases indiscriminately on either side of the
"host" coin, by another government, or to indicate revaluation.
Counterstamp
- The coin being counterstamped is placed between new dies and struck as if
it were a planchet, such as the holey dollars and dumps.
Cud - A lump on a coin, struck by a die from which a piece has broken
off.
Curved based letters - see fishtailing
D
Die break - Where a piece of
the die face has broken and lifted from the die, but still in place. A coin
struck from such a die will exhibit a die crack like line, around the edges
of the broken piece, and that part of the face of the coin effected, is usually
incused, or a step down like appearance.
Die cap - see Capped die
Die chip - A fragment breaking off a die. The metal flowing into the
resulting hole during striking, creating a raised lump on the surface of the
coin
Die clash - see clashed die
Die crack - Is were a crack has formed on the die, due to substantial
pressure or use. The metal from the planchet filling the crack when struck,
leaving fine irregular raised line/s on the face of the coin.
Die defect - An imperfection on a coin caused by a damaged die.
Die progression - A sequence of coins struck from the same pair of dies
and exhibiting a progressive change in the appearance of a particular die error.
Doubled Die - A common name for Hub-Doubling (see Hub doubling)
Double struck - A coin error, when a coin is struck twice by the die
Doubling - A common term used to describe the many types of Hub Doubling
and Machine Doubling.
E
Edge bite - see clipped planchet
Elongated Coin - An oval medalet usually produced deliberately by a roller
using a coin, token or medal as a planchet
Evasion - A close copy of a coin with sufficient intentional differences
of design or legend to avoid being in violation of the counterfeiting laws.
Also called an Imitation or Freak
F
Facsimile - An exact copy of a reproduction/original coin, possibly
marked with wording or a device to indicate it is a copy.
Fantasy - Is a piece/object purporting to be a coin, struck with dies
that were never officially authorized or using dies that were never used to
strike legal tender issued coins
Field - The flat area on the face of a coin that is unaffected by the
design
Filled die - A coin struck by a die that which had foreign matter, such
as dirt, grease, oil, metal fragments or a combination, filling some part of
the design, or sticking to the face of the die, preventing the coin metal from
flowing into and filling the design or making contact with the die in these
areas; shows as weak or missing design details and/or a rough irregular surface
in the effected areas. (See "struck thru" for individual types)
Fin - A varying sized raised fin-like device, a replica of the area under
Elizabeth 11's hair and back of neck, usually found above the date on pre-decimal
copper coins, that may have been caused by ghosting and or to a lesser extent
clashed dies or similar fault transmitted by the working die. (see Spur)
Fishtail/Fishtailing - A distortion of the letters of a legend caused
by differential outward flow of metal during the pressing of dies and/or hubs.
One specific instance of fishtailing is the curved-base lettering seen on some
George V pennies and halfpennies.
Flake/Flaking - see Lamination flaw
Flan - see Planchet
Flipped strike or Flipover Double Strike (US) - a coin which has been
struck correctly, and then has not ejected properly, is flipped over so that
its reverse is struck a second time by the obverse die, and vice-versa in regards
to the obverse side; they can be centred or off-centred
G
Ghosting - The impression of the Obverse showing through to the Reverse and vise versa. Caused by the use of soft planchets, over pressure on the presses and worn Dies. Can be light, medium or heavily ghosted, and appears on one side only, usually the reverse. These are not produced by clashed dies, but an occasional Die Clash mark may be observed on these types of coins
H
Hub doubling - The imperfect alignment of the hub pressings/blows during the die preparation, resulting in many different types of hub-doubled working dies. Coins struck by these dies will often exhibit a valley affect (a division or notching) on the serifs, legends and/or points of the devices. (Also read Machine doubling)
I
Imitation - see facsimile
Indented error - When two planchets are in the coining chamber at the
same time. The two planchets may overlap each other, be of different sizes,
or they maybe a blank and a coin together. See types below.
----- Types of indents -----
1. Indented strike - Occurs when two planchets are fed inadvertently
into the coining chamber, with one planchet partly overlapping (on top of) the
other. When the hammer die strikes this combination, the upper planchet will
be forced into the lower planchet, creating a depression which is shaped similar
to the upper planchet, and shows no design details in the indented area
2. Indented strike of smaller planchet - A scarce type of indent occurs
when a planchet intended for one denomination lands on top of a planchet from
a different denomination in the coining chamber
3. Indented second strike - Results from a planchet and a struck coin
coming together in the coining chamber, the design of the first strike (coin)
will be flattened and stretched out, in the indented area. The second planchet
showing signs of a brockage
J - K - L
Lamination flaw - Where a piece of metal has peeled away from the coin's suface, caused by a foreign substance such as gas oxides or dirt which become trapped in the metal strip, or if the strip folds over during the blank rolling process.
M
Machine doubling (MD) - Where the die has bounced or twisted on impact
and a second, lighter impression (not strike) could be delivered with the coin
shifting slightly, and will exhibit a spreading affect (displaced sideways or
appears pushed) of the serifs on the legends and/or devices. (Also see Hub doubling)
Metal flow - The movement of metal during the striking of a coin, in
order to fill the design of the Die and create the desired result. Stretch marks/Striations
on the surface of the coin, in the fields, can be attributed to incorrectly
annealed planchets.
Metal transfer - see ghosting
Misstrike - Used to describe various types of errors. Usually results
in coins that have only portion of the design appearing. Coins can appear as
struck off center and as a result can still be flat but more often bent at one
side so as to give the appearance of a high rim coin or a soup spoon shaped
coin.
Mule (Hybrid) - A coin struck from dies not originally intended to be
used together.
Multiple strikes - A coin struck more than once, as a result of not being
properly ejected from the coining press
N - O
Off centre - Said of a coin only partly resting within the coining chamber
at striking. Can be missing part or all of any edge reeding/device
Off metal strike - Any coin which has been struck on a planchet that
isn't the right metal composition for that type or denomination of coin
Overdate - The date made by a mint engraver superimposing one or more
numbers over a previously dated die
Overlapped planchet - see indented error
Overstrike - A totally full impression made with new dies over a previously
struck coin. (also see "counterstamp")
P
Pattern - A pattern struck as a coin/s in order to obtain
the final approval of the government or issuing authority before the general
circulating coinage is struck. May be struck off metal and can be unifaced or
full Obv/Rev arrangement.
Planchet - A rimmed blank, the size and weight of the finished coin,
on which a coin design is stamped. (also see "Blank")
Proof - Coins struck using specially prepared dies and planchets, under controlled
conditions. Struck 2 or more times under higher pressure. Designs maybe frosted, coloured or
hologram. In earlier times a proof was a "specimen" prepared under carefully controlled
conditions, perhaps with polished planchets.
Q - R
Ram strike - A planchet not sitting properly within the collar, forced
into the collar at striking by the die, creating a high rim or raise lip, and
at times struck off centre
Restrike - A coin struck from a genuine die at a date later than the
original issue.
Rim Burr - A tapered spear of metal impressed into the surface of the
coin, and they always occur at the rim
Rotation - see Alignment
S
Scalloped letters - see Fishtailing
Short planchet - see Clipped planchet
Slipped collar - See Ram Strike
Specimen - A coin with a special finish, less than proof in quality but
superior to the general circulating coin
Split Planchet - A type of lamination error, where the split can leave
a coin in two halves, one obverse and one reverse. As some do not break fully
open, a significant portion of the coin can be missing or can have the two halves
still attached at some point
Spur - A varying sized raised spur-like device, a replica of the area
under King George V's chin and his vestments, usually found alongside lettering
on older coins, that may have been caused by ghosting and or to a lesser extent
clashed dies or similar fault transmitted by the working die. (also see "Fin")
Striation - See Metal flow.
Struck outside the collar - (term becoming redundant) see Broadstrike
Struck partly outside collar - A coin that only partially sits within
the collar, leaving an uneven edge, and/or incomplete reeding. That part of
the coin outside the collar, having no restriction to metal flow, will exhibit
the traits of a broadstruck coin.
Struck thru ## - A general term describing any number of foreign objects
between a die and planchet at the time of striking. Also see Filled die
Struck thru dirt - Devices and/or lettering not being fully struck up.
Caused by a build up of dust in the design of a die
Struck thru grease - Incuse marks on the surface of a coin, generally
rough and irregular, caused by oil/grease or the like, depositing onto the die,
after it was wiped with an oily rag or oil weeping from the machinery
Struck thru lint - Small incuse mark/s on the surface of a coin caused
by stray hairs, threads and the like coming between a die and planchet
Struck thru object - An incuse impression of a miscellaneous object,
which has found its way between a die and planchet
T
Thin planchet - A planchet that is thinner than the tolerances allowed
for. Caused by a fault during the rolling of metal ingots (bars) or where the
ends of a metal strip have not been trimmed back far enough. These coins generally
exhibit a weak or soft strike
Trial piece - A coin struck to test the properties of a die. It may not
be a complete design, but, may be struck on different metals
U - V
Uniface - A coin which has been struck with a design on one side only.
The other side is blank. Normally uniface coins are patterns but ocassionally
are found as errors caused by a faulty striking process.
Unique - An item of which one example only is known to exist.
Unpublished Variety/Error - An example of a coin, token or medal with
a difference, ie - lettering, metal content, overdate unknown date etc, which
has not been listed in numismatic writings or in a journal.
Upset - A variation from the normal alignment of obverse and reverse
dies. More prevalent on pre-decimal coins, this was caused by one or both dies
rotating in the coining press. Nowadays, it only occurs as a machining error
as dies have keyways cut to prevent rotation.
W
Weak strike - A coin exhibiting an incomplete strike (not fully formed)
all over, or a partial incomplete strike of the design. Caused by insufficient
pressure to push metal into all the nooks and crannies of the die, improper
die spacing, or the planchet being thinner than normal. Often an Uncirculated
coin will look like a used example. Also see thin planchet
Wrong planchet - Any coin struck on a planchet that wasn't intended for
that denomination
X - Y - Z
*******
Participants in correlating list :- A.McGuire, D.Hughes,
I.Hartshorn, I.McConnelly, J.Himelfarb, J.Saxton, S.Wren
Main References:
Australian Coins and Banknotes by Greg McDonald
Australian Penny Varieties by Phil Bird
Coin World Almanac
Coincraft’s Standard Catalogue of English & UK Coins 1066 to Date
Coinweb CD - Australasian Currency
Official A.N.A. Grading Standards for United States Coins
Price guide to Mint Errors 6th Edition by Alan Herbert (USA)
Renniks Australian Coin & Banknote Values
Happy hunting top