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.

Indonesian students wearing paper masks take part in the East Java Mask Parade in Surabaya, Indonesia, 13 December 2015. Thousands of people participate in the traditional parade to preserve the mask custom among the younger generation. (Photo by Fully Handoko/EPA)

Carolaine Reis and her son Miguel Alves, residents of the Aglomerado da Serra favela, wear a protective mask against the spread of the new Coronavirus (COVID-19) made by the seamstresses of the Remexe Favelinha studio, in the Aglomerado da Serra favela, on April 13, 2020 in Belo Horizonte, Brazil. Facial masks follow the protocol and guidelines defined by the Ministry of Health. Around 6,000 masks have already been produced. The masks are being distributed to a part of the population and sold throughout the country, in the amount of 5 reais per unit. (Photo by Pedro Vilela/Getty Images)

Workers hang thousands of different colorful fabrics on iron wires tied between a bamboo framework and constantly turn them so that they dry perfectly in a flooded field in Narayanganj, Bangladesh on March 16, 2022. (Photo by Joy Saha/ZUMA Press Wire/Rex Features/Shutterstock)

A woman tries to take selfie photos in front of a photo spot featuring Christmas season scene and masks at Tokyo Mask Land, a face-mask theme exhibition and its speciality shop, amid the coronavirus disease (COVID-19) outbreak, in Yokohama, Japan on December 1, 2020. (Photo by Issei Kato/Reuters)

Cosplayer and super fan Sophia sits on the Iron Throne outside the Tower of London on Monday, August 8, 2022 to mark the launch of the Game of Thrones prequel, House of the Dragon, airing on Sky and streaming service NOW from August 22. (Photo by David Parry/PA Wire Press Association)

After finding the bricklaying business too full of ups and downs, this amazing young girl decided to take a shot at iron girdering for a change. She is Miss “Collie” Collier, a reporter for the Chicago Herald-Examiner. August 17, 1920. (Photo by Bettmann Archive/Getty Images)