Differences: Mint, Proof, Circulation, Legal Tender

How the coins are struck is the difference. Proof coins can be struck with polished dies on polished blanks with higher striking pressure than regular coins.




Probably, but I wouldn't say a face value always means it's spendable.
What constitutes legal tender probably varies from country to country but if it's issued as legal tender by an organisation that a government has authorised to issue legal tender, it's probably legal tender.

All money coined by a national government has a nominal intrinsic value placed upon a particular coin. All school children know what a quarter, dime, nickel, or penny is and how the addition of these coins can allow them to purchase a product that they desire.

This concept carrys over to mint sets. A mint set can be either proof (clad or silver) or an uncirculated coin set. It is not unusual to see any of these sets being broken down by people to either put the coin into their collections and then having the remaining coins placed into circulation for the purchase of everyday items at the face value of the coin. In fact this action is probably the number one reason as to how coins from the San Francisco mint do get into circulation. However, with the exception of the current years San Francisco struckATB quarter coins they are not intended for circulation.

People who spend a silver proof coin is really doing themselves a disservice because of the higher intrinsic value of the silver coinage. At today's precious metal value a silver ATB Quarter is almost 25 times its face value.

You can look up each of these and other terms in the CCF Glossary...


circulation

A term applied to coins that have been spent in commerce and have received wear.


circulation strike

An alternate term for Business Strike or Regular Strike. A coin meant for commerce.


Legal Tender

Coins and currency issued by the government as official money that can be used to pay legal debts and obligations.


mint set

A set of Uncirculated coins from a particular year comprising coins from each Mint. (Usually, this term refers to government issued Mint Sets, although for many years, it has been loosely used for any set of Uncirculated coins from a particular year. Also, the government Mint Sets issued from 1947 until 1958 were double sets.)


Proof

A coin usually struck from a specially prepared coin die on a specially prepared planchet. Proofs are usually given more than one blow from the dies and are usually struck with presses operating at slower speeds and higher striking pressure. Because of this extra care, Proofs usually exhibit much sharper detail than regular, or business, strikes. PCGS recognizes Proofs (PR) as those struck in 1817 and later. Those coins struck prior to 1817 are recognized as Specimen strikes (SP).


Proof set

A coin set containing Proof issues from particular year. A few sets contain anomalies such as the 1804 dollar and eagle in 1834 presentation Proof sets.