The mineral pyrite, or iron pyrite, also known as fool's gold, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold. The color has also led to the nicknames brass, brazzle, and Brazil, primarily used to refer to pyrite found in coal.
In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals.

A lion cub wakes in the morning sun at the Zimanga private game reserve in South Africa on April 9, 2022. (Photo by Calvin Kotze/Animal News Agency)

Visitors watch a California sea lion at the Smithsonian National Zoological Park on Thursday May 26, 2022 in Washington, DC. (Photo by Matt McClain/The Washington Post)

Performer and artist Aoi Yamada and film director Makoto Nagahisa perfom on stage during a conference at the Cannes Lions International Festival of Creativity in Cannes, France on June 21, 2023. (Photo by Eric Gaillard/Reuters)

A sick California sea lion with possible domoic acid poisoning is rescued to be evaluated by volunteers from CIMWI (Channel Islands Marine & Wildlife Institute) in Santa Barbara, California, on March 25, 2025. Over a hundred sea lions, dolphins and other marine mammals, including birds, have been sickened by domoic acid poisoning from algal blooms in Southern California since February, US media reported. (Photo by David Swanson/AFP Photo)

A soldier of the French Foreign Legion holding his regiment's banner at Bar Hacheim in Libya, circa 1940. (Photo by Three Lions). P.S. All pictures are presented in high resolution.

A tow car for the children's “Grand Prix” races which take place in a parking lot in Livonia, Michigan a suburb of Detroit, circa 1955. (Photo by Three Lions/Getty Images)

A Palestinian man carries a lion cub as he shows it to children in Rafah refugee camp in the southern Gaza Strip on December 4, 2019. (Photo by Ibraheem Abu Mustafa/Reuters)