This coin was on board the SS Republic when it sank in 1865 and spent decades underwater.
Because of this there is the shipwreck effect as noted by NGC.
SHIPWRECK EFFECT B — A coin showing evidence of light surface disturbance from immersion in saltwater. May have some areas of moderate disturbance, not affecting central design elements. Coin possesses above-average eye appeal for shipwreck recovery coin.