It looks like a copy of the gold New York doubloon or Brasher doubloon (note the EB on the eagle's wing). If yours is genuine (which is highly, highly unlikely) it would be only the eighth known example.
The first step is to determine if it gold. If it is not gold it is not a Brasher doubloon. If it is gold I would suggest having a knowledgeable coin dealer take a look at it.
Your coin does not appear to be gold but you may want to weigh it. According to the Red Book "The gold pieces Brasher made weighed about 408 grains . . . " (That is about 26.44 grams by my calculation.)
