Faujasite is a mineral group in the zeolite family of silicate minerals. It is a zeolite mineral consisting of sodalite cages connected through hexagonal prisms. The group consists of faujasite-Na, faujasite-Mg, and faujasite-Ca. They all share the same basic formula: (Na2, Ca, Mg)3.5[Al7Si17O48]·32(H2O) by varying the amounts of sodium, magnesium, and calcium. This mineral is occurring in colorless octahedral crystals in the amygdaloid of the Kaiserstuhl in southern Baden. It is a hydrous silicate of aluminum, calcium, and sodium.
It was named for Barthélemy Faujas de Saint-Fond (1741–1819), French geologist and volcanologist.
- Category: Zeolite
- Formula: (Na2, Ca, Mg)3.5[Al7Si17O48]·32(H2O)
- Crystal system: Cubic
- Crystal class: Hexoctahedral (m3m)
- Color: Colorless, white
- Crystal habit: Octahedral or rarely trisoctahedral crystals up to 4 mm in size
- Fracture: Uneven to conchoidal
- Tenacity: Brittle
- Mohs scale hardness: 4.5-5
- Luster: Vitreous to adamantine
- Streak: White
- Diaphaneity: Transparent
- Specific gravity: 1.92–1.93
- Optical properties: Isotropic
Faujasite occurs in vesicles within basalt and phonolite lava and tuff as an alteration or authigenic mineral. It occurs with other zeolites, olivine, augite, and nepheline. It occurs as a rare mineral in several locations worldwide and is also synthesized industrially.
Faujasite was first described in 1842 for an occurrence in the Limberg Quarries, Sasbach, Kaiserstuhl, Baden-Württemberg, Germany.
Faujasite is used above all as a catalyst in fluid catalytic cracking to convert high-boiling fractions of petroleum crude to more valuable gasoline, diesel and other products. It is also used in the hydrocracking units as a platinum/palladium support to increase the aromatic content of reformulated refinery products.