An important part of determining the value of a silver coin, particularly a rare or unusual one is silver coin grading.
Some of the factors used to determine the value of a silver coin include:
The quality of the silver coin when it leaves the mint. It is possible that even proof coins can have very tiny imperfections that result during the striking process. If there is even so much as a tiny hair or dust mote between the coin and the die when it is struck an imperfection will be left.
The weight of the coin and how much silver it contains. A silver coin should be 99.99 percent silver or thereabouts and certainly the specifications should be known.
If the coin is in it's original seal or bubble. The less exposure to air and accidental touching the better.
If a certificate comes with the coin describing the qualities and specifications of the coin.
It is vitally important that when you receive a coin fresh from the mint that you do a careful examination of both sides of the coin to ensure there are no imperfections. This should be done while the coin is in its protective holder or bubble and should, under no circumstances, ever be removed and handled. Hairline cracks can be created just by handling a silver proof coin and this is the reason why many silver coins are downgraded from perhaps Proof-63 and Proof-64 instead of Proof-69 or Proof-70. Anything that touches the surface of the coin can leave hairlines.
Silver coins should never be cleaned as even cleaning a silver coin can adversely affect it’s grading. Unless it is professionally done cleaning of silver coins should be left to a professional. Chemical cleaning can sometimes remove a layer of silver leaving a bright surface underneath. This can be spotted by a professional grader however as can mechanical cleaning where abrasives are used. These will commonly scratch the surface of the coin and reduce the grading and therefore the value also.
It is probably wiser to avoid any cleaning whatsoever as the fact of cleaning itself may affect the grading of the silver coin.
For older silver coins the amount of circulation wear or, for an uncirculated mint coin (MS60 through to MS65) how close it resembles a "perfect" condition when first struck.
Proof silver coins are struck in a special way with extra attention to the striking process and these silver coins are meant for collectors primarily these days.
All rare silver coins should be independently certified for grade and authenticity by a leading independent grading services.
Certified silver coins protect both the buyer and the seller by providing protection and an agreed grading and value for the silver coin.
Silver coin grading is very important to ensure you can demonstrate the true value of your coin collection and well worth the small amount it costs to obtain certification.