Precious Metal – Gold/Silver/Platinum
Specific Dates and Mint Mark (a letter indicating where the coin was made)
Demand – How many collectors want the coin
Condition – Original, unaltered, uncleaned. Better condition, better value.
Eye Appeal – Is the coin appearance above average?
Original vs. Cleaned Condition– Cleaned coins are worth a small fraction of the value of original coins.
Varieties, Errors, Mistakes – Mint errors are often highly collectible.