Fine, with a rating of 12 on the scale from 1 (being the worst) and 70 being the best. Such a coin isn't in the greatest condition but has everything readable.
For a coin it is just worth the value stamped on it i.e. the value on it's face So a common coin is worth face value, but a rare coin is worth more than face value.
South African rand
Coin grades consist of broad categories designated by letters, and within each of those there are finer subcategories indicated by numbers. "F" stands for "Fine", a grade meaning moderate wear. Within the F grade there are 8 numeric levels ranging from 12 to 19. Thus an F12 is the lowest grade a coin can have within the Fine category and an F19 is the highest. A coin that's more worn than F12 falls into the VG (Very Good) or lower category, and a coin that's better than F19 becomes VF (Very Fine) or higher.
To burnish metal is to polish it so that it shines. This is not something that coin collectors would do to a collectible coin, since some small part of the coin would be polished away by this process, and the objective of coin collecting is to keep the coin as close as possible to its original condition when minted. If you are not a coin collector, then burnishing a coin is irrelevant to its value.
Could you please explain what you mean by "nimm"? What is the coin's denomination? If it is foreign, do you know what country it came from? What image(s) and/or inscription(s) are on the coin?
If you have this coin, count your blessings! In a mint state of fine (F12), its value is worth: $120,000!
You have in your possession a 1897 Coronet Head $5 Half Eagle - if this coin is in fine condition (F12), its value is: $250.
You possess a Coronet Head $5 Half Eagle. A 1905 coin in fine condition (F12) is worth: $250.
A 1906-D Coronet Head $10 Eagle gold coin in fine condition (F12) is worth: $ 525.00.
You possess a Coronet Head $5 Half Eagle - a 1872 coin in fine condition (F12) is worth: $ 400.00.
You have a Coronet Head $5 Half eagle coin - if this specific 1906 coin is in fine condition (F12), it is worth: $ 250.00
You possess a Coronet Head $5 Half Eagle coin - if this coin was minted in 1897 and it is in fine condition (F12), its value is: $250.
You possess a Coronet Head $5 Half Eagle - a 1872 coin in fine condition (F12) is worth: $ 400.00.
Assuming you mean Indian Head cent 1887 retail value is $6.00
A 1904 $5 Gold Coin - aka - Coronet Head Half Eagle - is worth in fine condition (F12): $250; if its mint state is MS60, the value rises to: $400.
Wow! You have a fairly rare coin in your possession - a Silver 3 Cent piece, minted in the year of 1867, in fine condition (F12) is worth: $500.00.The US Treasury also minted in the year of 1867 a Copper-Nickel 3 Cent piece - if this is the coin you possess, its value in fine condition (F12) is: $25.00.
It increases the value on the coin.