This is an NGC certified proof Jefferson nickel planchet, with polished surfaces giving them a distinctively different appearance from a business strike nickel planchet.
The planchet is ex-San Francisco Hoard, which is a large hoard of various types of proof and other planchets (various denominations) was recently discovered in the last few years.
Proof nickel planchets are very scarce, and although there are some on the market right now, historically these almost never came up for sale. An opportunity to buy something which will doubtless be very tough to find in the future as these get spread out among collections.
NGC Proof with brilliant proof surfaces--exceptionally nice example.