please show me a error on a 1780x m thereisa coin
A restrike is a coin that is minted later than what the date says on it. For example, all examples of the Maria Therisa Thaler from 1780 onwards are dated 1780, and the Austrian mint still produces them today, but they are all dated 1780. Re-strikes are not the same as reproduction coins because re-strikes are either authorized by the mint that first produced them (as in the case of the thaler) or struck from authentic dies later on (as in confederate half dollar restrikes). It is important to know if a coin you are buying is a restrike or not if you are looking for a particularly old coin, because some less knowledgeable or fraudulent dealers will make the date on the coin a major selling point, despite the coin not being struck in that date.
I assume you're referring to a Maria Teresa thaler, probably dated 1780.This is actually a bullion coin that's been struck in a number of countries, with the same date and design ever since then. It's sold for its silver value, not for spending. It sells for a bit more than the price of 1 oz of silver. That number changes a lot so you'll need to look in the business section of a newspaper or Google silver AND "spot price" to get an idea of its current value.
There are a few things to realize about a 1780 Maria Theresa Thaler: Your coin was NOT minted in 1780, the Austrian mint has produced Maria Theresa Thalers fixed at Maria Theresa's death in 1780, most likely your coin was made in the 20th or 21st century. That doesn't mean your coin is worthless it just means that your coin isn't several hundred years old. Since they are restrikes, they don't have much of a premium over silver value, today they run around $25-30 depending on silver price and the condition of the coin.
No US coin bears an "F" mint mark
Mintmarks identify which mint the coin was made at.
A mint condition coin is a coin that is in pristine condition, as if it has just been produced at the mint. It will have no signs of wear, scratches, or damage, and the details on the coin will be sharp and well-defined. Mint condition coins are highly valued by collectors due to their rarity and quality.
The letter is known as the mint-mark and tells where the coin was made. A coin having a P mint-mark (or no mint-mark on some coins) was made in Philadelphia, a coin having an S Mint-mark was minted in San Fransisco, a coin with a D mint-mark was minted in Denver.
No. However, there is a George Washington mint coin.
If there isn't a mint mark on a US coin, usually it means that such a coin was minted in Philadelphia.
Mint condition, Mint State, & Uncirculated all mean the same thing. Unused, no wear, as in the same condition as from the Mint when the coin was struck.
The Denver mint is on a coin showing the letter D, this means it was made in Denver, sometimes depending on the coin and year the D mint can be worth some money.
Harriet Tubman has never been on a US Mint Coin.