This article, authored by Donna L. Whitney and Bernard W. Evans, discusses the evolution and expansion of a system of abbreviations for rock-forming minerals. The original list, provided by Kretz (1983), has been widely accepted for its logic and simplicity. Over the years, several revisions have been made, including those by Spear (1993), Holland and Powell (1998), and Sivola and Schmid (2007). The authors propose an updated list with 371 entries, reflecting recent research in high- and ultrahigh-pressure metamorphic terrains, solid-solution series, extraterrestrial samples, and the increasing relevance of accessory minerals in petrology. The two most commonly used systems—Kretz (1983) and Holland and Powell (1998)—differ in style and concept. Kretz's system uses 2-3 letter abbreviations with uppercase first letters, while Holland and Powell's system uses 1-5 letter lowercase abbreviations. The Kretz system includes selected intermediates in solid-solution mineral series, whereas the Holland and Powell system focuses on end-members with available thermodynamic data. The authors aim to be inclusive in their selection of minerals, listing some that may have questionable status according to the International Mineralogical Association. They also include hypothetical and synthetic phases, as well as an abbreviation for "liquid." The updated list aims to make mineral identities obvious and unambiguous, with specific rules for abbreviation assignment. The article acknowledges contributions from Marc Hirschmann and Howard Day and provides references to key sources.This article, authored by Donna L. Whitney and Bernard W. Evans, discusses the evolution and expansion of a system of abbreviations for rock-forming minerals. The original list, provided by Kretz (1983), has been widely accepted for its logic and simplicity. Over the years, several revisions have been made, including those by Spear (1993), Holland and Powell (1998), and Sivola and Schmid (2007). The authors propose an updated list with 371 entries, reflecting recent research in high- and ultrahigh-pressure metamorphic terrains, solid-solution series, extraterrestrial samples, and the increasing relevance of accessory minerals in petrology. The two most commonly used systems—Kretz (1983) and Holland and Powell (1998)—differ in style and concept. Kretz's system uses 2-3 letter abbreviations with uppercase first letters, while Holland and Powell's system uses 1-5 letter lowercase abbreviations. The Kretz system includes selected intermediates in solid-solution mineral series, whereas the Holland and Powell system focuses on end-members with available thermodynamic data. The authors aim to be inclusive in their selection of minerals, listing some that may have questionable status according to the International Mineralogical Association. They also include hypothetical and synthetic phases, as well as an abbreviation for "liquid." The updated list aims to make mineral identities obvious and unambiguous, with specific rules for abbreviation assignment. The article acknowledges contributions from Marc Hirschmann and Howard Day and provides references to key sources.