Berthierite is a rare iron antimony sulfosalt and not often found in good crystallized specimens. This piece is from the classic locality, the Baia Sprie Mine (Felsőbánya Mine) in Romania featuring dozens of acicular, silvery-grey needles of berthierite in nearly parallel growth, free of matrix. This rich specimen is beautifully accented with a variable iridescent tarnish, giving the piece much color and character. A wonderful example of this rare and classic material from a locality that was mined continuously from the 14th Century until 2006. From the collection of Julio Martínez (València).

Group of very elongated prismatic crystals, in parallel growth, very brilliant. The back side has a coating of quartz microcrystals. A piece from the Astor collection acquired in 1974 from Bailey Minerals (Ángel Jesús Talabán García, Segovia 1942-Madrid 2007).