Anorthoroselite (formerly Roselite-β) with Roselite and Cobaltaustinite (rare)

Item Description

A cool association specimen from the famed Aghbar Mine featuring crystals of Anorthoroselite (formerly Beta-roselite or Roselite-β) along with Roselite and Cobaltaustinite. Anorthoroselite was renamed in 2022 for the fact that the "anortho" prefix means that the crystals have no right angles, as they are triclinic dimorphs of Roselite, which is monoclinic in habit. They have the same chemistry (hydrated calcium cobalt arsenate), and I think it's safe to say that the best examples are those from this locality, and the Bou Azzer Mine in Morocco. Cobaltaustinite is a rare calcium cobalt arsenate mineral, and the cobalt-analogue of Austinite and Nickelaustinite. This piece is a showy example featuring intense fuchsia colored Anorthoroselite and Roselite crystals sitting on dark olive-green colored crystals of Cobaltaustinite in between layers of pale pink cobalt-bearing Dolomite on matrix. The piece is best seen with magnification, and we've done our best to illustrate the quality in the close-up photos.
This piece comes from the collection of John Dagenais (#JD-408), a collector from the Pacific Northwest. John started collecting in 1969 and progressed to micromounting, and later built suites of specimens from the Chuquicamata Mine in Chile, the Tsumeb Mine in Namibia, the Majuba Hill Mine in Nevada, the Black Pine Mine in Montana and the Tintic District in Utah, among other places. You can visit John's mindat profile at https://www.mindat.org/user-647.html.