I have an unusual quarter here both in weight and appearance can somebody tell me more?

JAD0311

TomB

Howdy and welcome.

The quarter appears environmentally damaged. It is still worth a quarter, however.

hfjacinto

Actually looks like it was washed in acid, you can see the copper core show thru. Hence the weight loss, some of the clad is eroded away.

291fifth

The coin probably spend considerable time buried in soil that caused severe damage to its outer clad layer. It was then found and harshly cleaned. It is not an error.