Garnet, the archetypal cubic mineral, grows tetragonal.

ABSTRACT: Garnet is the archetypal cubic mineral, occurring in a wide variety of rock types in Earth's crust and upper mantle. Owing to its prevalence, durability and compositional diversity, garnet is used to investigate a broad range of geological processes. Although birefringence is a characteristic feature of rare Ca-Fe³⁺ garnet and Ca-rich hydrous garnet, the optical anisotropy that has occasionally been documented in common (that is, anhydrous Ca-Fe²⁺-Mg-Mn) garnet is generally attributed to internal strain of the cubic structure. Here we show that common garnet with a non-cubic (tetragonal) crystal structure is much more widespread than previously thought, occurring in low-temperature, high-pressure metamorphosed basalts (blueschists) from subduction zones and in low-gra

SUBMITTER: Cesare B 

PROVIDER: S-EPMC6789019 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature