Antique Czech Black Navette Mourning Brooch

Antique navette shaped mourning brooch marked Made in Czechoslovakia on the back.

The faceted jet material doesn’t seem to be glass and might be another synthetic material—I’m not quite sure.

Relatively good condition but the metal on the back has some corrosion Pin holds well in c-clasp.

Measures approx 1.8” x 0.9”