Erythrite

Erythrite is a magenta deep red colored mineral. Its distinctive color is caused by its cobalt content. Erythrite is a secondary hydrated cobalt arsenate mineral. Large crystals on specimens are very uncommon. Individual crystals are normally elongated, thin and bladed with a distinct angled termination. Crystals are often striated. Most Erythrite occurs as radiating acicular, concretions, or masses in the oxidized zone of cobalt and nickel deposits.

Its structure is similar to Annabergite which has nickel replacing cobalt in the Erythrite structure. As the nickel content increases, the color progressively changes from red to the apple green Annabergite color. Erythrite was first found in 1832 in Schneeberg, Saxony, Germany and gets its name from the Greek word “erythros” (which means red). Erythrite, or "Cobalt Bloom" as it is called by miners has a very noticeable bright red-purple color that was used to spot veins of cobalt-bearing ore. You may hear some collectors refer to Erythrite as “Red Cobalt” which is an incorrect slang term.

Notable localities include Schneeberg, Saxony, Germany; Joachimsthal, Czech Republic; Cornwall, England; Bou Azzer, Morocco; Lemhi County, Idaho; Sonora, Mexico; Mt. Cobalt, Queensland and Mingary, South Australia. Most Erythrite in these localities is found in the form of crusts, but specimens from Morocco have larger crystals.