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Types of Coins |
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 Proof
Coins
Proof coins are the masterpieces of our craftsmanship. Clean, good quality steel is used to make proof dies. The die impression is grit-blasted with very fine zirconium sand to give the surface a frosted finish – the common term for this is sand-blasting. The surrounding background is then highly polished. Hand polishing of the sections of the die face is performed under a microscope and takes two to three hours. To achieve a mirror-like finish, different grades of diamond lapping paste are applied to the surface and polished with wooden sticks (usually soft birch wood). This is followed by polishing with a soft felt pad attached to a dental drill. The entire face is covered with clear tape and then, using a fine scalpel, the tape is cut away leaving the design exposed. This area is sand blasted again and given an even frosted appearance and a clean sharp profile around the impression. After polishing, the die is chrome-plated or titanium nitride coated to resist damage from minute foreign particles and to extend the die life. This in turn reduces the number of times the die is refurbished. Proof coins are manually and individually coined in a specially designed and air conditioned environment. Laboratory coats, hair ties, gloves, sticky mats on the floor, lint free material to wipe dies, and fans continually blowing air across the die in the coining presses are some of the measures taken to minimize the risk of blemishes on the coins. On each manually operated press, using forces of up to 360 tons, we can produce about 500 proof coins per day. Within the coining press a collar is used to restrain the blank. The size and shape of the collar determines the shape of the finished product.
The operator inspects each coin and then Quality Control randomly examines coins within every batch. If one fault is found the entire batch is thoroughly examined. Finally, proof coins made from bronze, cupro nickel, aluminum bronze and sterling silver are sprayed with a nitro-cellulose lacquer to protect against oxidation. The coins are inspected once more. Proof coins are usually packed into capsules and high quality display packaging; along with information about the coins. |
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Un-circulated
Coins
Un-circulated coins are
manufactured in much the same way as circulated
coins except for the following:
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| Frosted Coinage
Frosted Un-circulated (Frunc) coins are very similar to un-circulated coins but with the following differences: The background or ‘field’ of the die is finely sand-blasted and the impression is polished to a bright finish. This creates a contrast that enhances the detail of the actual design. Also the frosted and polished areas are in reverse to that on a proof coin, so that the image has a polished appearance, and the field is frosted |
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| Medallions
Small medallions up to about 40mm diameter are manufactured much the same way as coins and the finish varies depending on the client’s specification. The finish may be "as struck" with the natural metal colouring, electro-plated in metals such as gold and silver or given an ‘antique’ appearance by using various chemical treatments. Medallions with natural or antique finishes are usually clear lacquered at the final stage to enhance and protect their appearance. Larger medallions, particularly those with deep relief require very high pressures to form the designs. Hydraulic presses with capacities of up to 600 tonnes are used to coin these medallions which may need to be struck several times with interstage annealing (softening) between each strike. |
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| Medals
The term medal usually indicates that there is provision for a ribbon or cord to be attached to hang from the neck or to pin to a jacket or uniform. Medals are very often shaped other than round and most are made by coining, trimming off the excess metal around the profile and piercing a hole or slot for the ribbon. Others may have the ribbon suspender soldered or welded on in a separate operation. Medals are usually in uncalculated finish because the proof and frunc finishes do not wear well. They may also be plated and include areas of colored enamel. |
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| Tokens
The manufacture of tokens utilizes the same process as circulating coins. The packaging may vary depending on clients' individual needs. |
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High
quality replicas ancient coins, early coins, modern coins,
Greek coin reproductions , Roman coin reproductions,
Biblical coin reproductions, Spanish New World treasure
coins, Ancient Greek Coins, Reproductions of Early and
Modern Coins, Colonial coins, Spanish Treasure Coins,
English Coins, Ancient Roman Coins, Ancient Biblical Coins,
Modern US Coins Dunston Mint Makes and sells high quality
replicas of ancient, early, and modern coins. We specialize
in reproducing of original pieces in private collections and
famous museums, such as the British Museum. A wide variety
of Greek, Roman, and Biblical coin reproductions of the Old
and New Testament are offer in the Ancient Coin Replicas.
Early and modern coin replicas of the British Isles, Spanish
New World treasure coins, colonial US coins, and US minted
coins are found in the Early and Modern Replicas section. |
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Operators,
with gloves and/or tongs, place the blank onto the coining press and
strike it up to 4 times. The number of strikes is dependent on the
size and the depth of relief. The die is wiped with alcohol, to
remove any dust, before the next coin is struck.
