Home > American Minerals – August 22 > MS1423 Benitoite


Benitoite is a barium titanium silicate. The name denotes its occurrence near the source of the San Benito River (Louderback & Blasdale, 1907). Its formal description by Louderback & Blasdale (1909) remains one of the most comprehensive mineral descriptions ever published. The discovery of benitoite greatly excited crystallographers, as benitoite became first example of a theoretical crystallographic point group 6m2, also called the ditrigonal dipyramidal crystal class, matching a prediction from 1832 (Rogers, 1908).

This specimen hosts a 14 x 14 mm benitoite crystal on blue schist matrix. The blue schist consists of an amphibole, formerly crossite, now defined as glaucophane. This benitoite crystal has incorporated a bit of glaucophane, making it what locals call a "rocky" crystal. An affordable benitoite crystal showing its trigonal symmetry.

Price: $100

Item code: MS1423

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