How do you know if a coin is uncirculated?
An uncirculated coin is just that, never been spent or used in change, and should not have any evidence of circulation such as small dents, scratches, nicks and should have no signs of wear. All edges should be sharp and clearly defined.
The flat surfaces of the coin show any dents, nicks and scratches much more readily, and the lettering, design images and the edge of the coin will reveal any wear first.
A magnifying glass will help a lot.
Most issuing authorities will prepare sets of Mint Uncirculated coins each year in a suitable packaging to prevent any damage and to protect the coins from being handled.