Cobalt Bloom, learn more about the mineral Erythrite and the rare and beautiful crystals it forms. 

Erythrite from Bou Azer district in Morrocco. Erythrite crystals like this are rare, typically it forms in crusts.

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What is Erythrite?

Erythrite is a mineral that can form rare and vivid red crystals. Its chemical formula is Co3(AsO4)2 · 8H2O, Hydrated Cobalt Arsenate. Erythrite forms a solid solution series with Annabergite. It is found near Cobalt, Silver and Nickle deposits and is also known as Cobalt Bloom. As lesser known and visually striking mineral, Erythrite is popular among collectors. While less common, Erythrite is also sought for particular metaphysical or spiritual purposes. Erythrite's name comes from the Greek for red, “erythros”.

Erythrite Appearance

Erythrite crystals display a range of reds, from light pink to vivid magenta to a dark crimson. They also have multiple forms; Erythrite crystals can be radial or stellate aggregates, drusy or fibrous. Common Erythrite is powdery and massive, while striated, prismatic crystals are quite rare.

Also known as ‘Cobalt Blooms’, Erythrite is most commonly found growing as brightly colored crusts on Cobalt minerals.   Because Erythrite is easy to spot by miners, Erythrite is used as an indicator by prospectors who are looking for Cobalt - Silver - Nickel deposits.

Erythrite Mineral information

Erythrite was named in 1832 by François Sulpice Beaudant. Its name comes from the Greek for red, “erythros”. Erythrite is a member of the Vivianite Group, which is a small group of rare hydrated phosphates minerals with similar structures. It is an Arsenate mineral, a rare subset of minerals that form only under special circumstances. Erythrite forms a solid solution series with Annabergite. In Annabergite, the Cobalt is replaced by Nickel, creating a green mineral. It is also known as ‘nickle bloom’.

  • The Chemical Formula for Erythrite: Co3(AsO4)2 · 8H2O Hydrated Cobalt Arsenate
  • Color: Crimson Violet to red also pale rose and magenta pink
  • Luster: Sub-Vitreous, Waxy, Pearly, Dull, EarthyHardness:1½ - 2½Specific Gravity: 3.06
  • Crystal System: Monoclinic
  • Member of: Vivianite Group

Erythrite Locations

Saxony, Germany is the classic type locality of Erythrite. It was first found here, forming in bright radiating sprays. Until recently, Schneeberg was considered to be the finest occurrence of this mineral but today, there are few specimens coming from this location. Morocco, however, has become the most popular place to source high-quality specimens of Erythrite.

The largest and some of the most vivid Erythrite crystals come from the Bou Azer district in Morrocco. This part of Morocco has produced gorgeous, ‘masterpiece’ specimen. Notable mines here include the Aghbar Mine and the Agoudal Mine.

Erythrite has also been found at Mount Cobalt in Queensland, Australia. Other variations have been found in Mexico and Ontario. The pink crusts of Erythrite found in Canada have typically indicated a silver deposit.

While the United States does not have any significant sources of Erythrite, there have been small pink crusts found at the French Creek Mines in Pennsylvania and the Blackbird District in Idaho.

Toxicity | All minerals should be handled responsibly

Because Erythrite contains a natural Arsenic, a toxicity warning is necessary on most specimens. New collectors may be wary of minerals containing Arsenic, but with simple hand washing and common sense, they should pose no greater threat than any other mineral. You can certainly handle Erythrite, but if consumed in significant quantity, or crushed up and inhaled, Erthyrite would be toxic. This is not a mineral for children and should be kept in a safe location.


See all Available Erythrite Specimens Here