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Your piece is a bronze folles of Maximinus II, struck circa 312 AD.
It depicts Sol* holding a cornucopia, and the mintmark ANT tells us that it was struck at the Antioch mint.
The brassy colour, as noted, appears to be the result of improper chemical cleaning - there are some bronze hints showing, though.
Rotations can vary widely for ancient coins.
*Sol, the Sun God, was a predominant religious figure in Rome from the 200s into the early 300s, until Constantine's open conversion to Christianity in 312 AD led to the rise of the monothestic God.