Hureaulite , Reddingite Locality: Cigana claim (Jocão claim), Galiléia , Doce valley, Minas Gerais , Southeast Region, Brazil ( Locality at mindat.org ) Size: 5.9 x 4.9 x 3.9 cm. This pegmatite is known for its suite of high-quality phosphate species, more than for gem crystals. It is very similar, in fact, to the famous Tip Top Mine in South Dakota for the major phosphate species found. However, hureaulite from this locality has a more beautiful, intense rich color and lustre, and is arranged in such pretty aggregates against contrasting lustrous brown reddingite, that I consider these to be among the more beautiful examples of the species. Usually you find the hureaulite dispersed as a flat carpet of small 2-5mm crystals on matrix shards. Few specimens have relief and well-defined aesthetics: but this piece has a sharp, superb cluster approximately 3 cm tall perched atop the specimen. It is 3-dimensional and leaps out. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Reddingite
Reddingite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Mn²⁺₃(PO₄)₂·3H₂O.
It crystallizes in the orthorhombic crystal system. It is a member of the Reddingite structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 3.1–3.24; White streak; Vitreous to subresinous luster; optically biaxial.
IMA symbol Rdd, IMA status: approved, named in 1878.
A rare secondary hydrothermal alteration product in zoned complex granite pegmatites.
It is found associated with Dickinsonite, triploidite, triplite, lithiophilite, fairfieldite, eosphorite, huréaulite, rhodochrosite.
The name refers to Redding Township, Connecticut, USA, within which the first specimens were collected, near Branchville.