The medal's obverse bears shoulder-length portrait of Native American woman within central roundel, facing left, surrounded by ornate border of fruit and flowers with four superimposed circular medallions bearing letters "XX", "C", "I", and "A," counter-clockwise.
The reverse bears large flower at center, surrounded by legend within line border, XX CONGRESSO-INTERNACIONAL DE AMERICANISTAS / RIO DE JANEIRO / 1875 BRAZIL 1922
The International Congress of Americanists is an international academic conference for research in multidisciplinary studies of the Americas. Established August 25, 1875 in Nancy, France, the scholars' forum has met regularly since its inception, presently in three year increments, with the exception of World War II. Its meeting location alternates between Europe and the Americas. Congress members come from a variety of disciplines, including anthropology, archaeology, art, education, economy, geography, history, human rights, law, philosophy, linguistics, sociology, and urban studies.
The circular medal measures 61.5mm in diameter and was struck in copper. Neither mintage, nor mint, nor artist are known to me.