What this coin looks like (obverse, reverse, mint mark location, special features, etc.):
The 1869/9 (9 Over 9 RPD) Indian Head Cent (Penny) is a Repunched Date error. This can be best identified by noticing a doubling of the number "69" where the primary date was stamped on top of the same 1869 date. Parts of the number "69" can be seen above or over the primary date as indicated by the arrows in the example image of this coin above.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD