What is circulated and uncirculated coins?

Uncirculated means a coins has not had any wear, like what a coin might sustain while used in commerce. Often, minor "bag marks" can be seen on uncirculated coins as a result of rubbing against one another while inside the canvas bags in which they are transported, and during the production process itself. An uncirculated coin should grade at least MS-60, but may show tarnish, toning, spotting, or discoloration.

These imperfections will not be observed on proof coins, which are manufactured differently to produce coins with more detail and a more polished appearance.

Proof coins are minted using specially prepared and polished dies and polished blanks or planchettes. Proof coin will have a mirror like finish on the flat surfaces and are usually sold in some form of packaging to protect the high quality finish.

Collectors of uncirculated and proof coins should store them in archive-quality cases, or at least handle them with cotton gloves to prevent skin oils from degrading the finish.