a. The process by which new minerals form in place within a rock during or
after its formation, as by replacement or recrystallization, or by
secondary enlargement of quartz overgrowths. AGI
b. Any process involving crystal growth in situ, i.e., subsequent to the
origin of its matrix or surroundings but not a product of transformation
or recrystallization, customarily reserved for low-temperature sedimentary
environments. Ant. allogenesis. Adj. authigenic; authigenous. Adv.
Dictionary of Mining, Mineral, and Related Terms