1999-P New Jersey quarter struck on an experimental alloy planchet. The coin is brassy-green colored, and closely resembles a Sacagawea dollar's metal. This coin's planchet is the yellow brass color and also has a copper core, which can be seen in the edge view holder it's in. There are a number of scratches on the obverse side which occurred before strike, and so are not damage but part of the mint error itself. The planchets appear to have been cut-down to size, and so perhaps that has something to do with the scratches since the cutting method used was crude for all the experimental quarters, and the rims show roughness from the cutting that the mint employees did.
It is not certain what the purpose of these was, but it could be conjectured that they were experimental issues used for testing alloys for the Sacagawea dollar, which was scheduled to be released in 2000 (these are 1999 coins.) Whatever the purpose, they are rare, with approximately 5 examples known for each state quarter minted in 1999, and also an example known for the 2000 Massachusetts quarter.
PCGS MS-63 with flashy, lustrous surfaces and no problems (PCGS discounted the grade due to the pre-strike scratches, and the coin should have graded MS-67 or thereabouts.)