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.

These beautiful shots may look like works of modern art – but they are actually close-ups of chemical reactions. The works were snapped with the help of a group of scientists from the University of Science and Technology of China (USTC) in Anhui, China. Here: Zinc reacting with lead nitrate in a soft gel to form lead crystals. (Photo by Yan Liang/Caters News)

Forgotten Guerrero. A female member of the community defence force holds her weapon. Since early 2019, the village has been attacked repeatedly by Los Ardillos cartel, prompting residents to take action. Rincón de Chautla, Guerrero, 10 June 2019. (Photo by Alfredo Bosco/Luz with the support of Le Figaro Magazine, Winner of the 2020 Humanitarian Visa d’or award, International Committee of the Red Cross/International Festival of Photojournalism 2020)