Bronzite - a bronze-colored variety of Enstatite (Pyroxene). 
 
 
From: Mangabal, Sanclerlândia, Goiás, Brazil. 
 
 
Sample measuring 3.5 x 3.5 x 1.0 cm and weighing approximately 25 grams. 
 
 
Its main attraction is the "cat's eye" effect or submetallic luster. This phenomenon occurs due to aligned microinclusions of iron oxides (such as magnetite or ilmenite).