It's a shield/mask made in the early 1800s from brass and gold chips. It's about 8 inches wide and 12 inches high.
I came across it at work. Someone threw it out.
Thank you for submitting your item for appraisal. This appears to be a 20th century lost wax casting plaque from traditionally West Bengal, India, so called Dhokra or Dokra brass, which today is manufactured in many rural areas in India. The estimate is based on similar items sold at auction. Prices in the trade are usually higher and can vary.