Almagreraite, Cu ²⁺ ZnMn ⁴⁺ ₃ O ₈ , a new mineral with a nolanite-related structure.

The new mineral almagreraite (IMA2025-025), Cu 2+ ZnMn 4+ 3 O 8 , was found on the dump of the Repblica Romana mine, Sierra Almagrera, Cuevas del Almanzora, Almera, Andalusia, Spain, where it occurs as tapering prisms or blades up to about 0.4 mm in length, commonly forming subparallel to divergent aggregates.It is a secondary mineral intimately associated with well-crystallized blades of malachite on a matrix consisting of well-crystallized goethite and massive friable hematite.Crystals are black and opaque with submetallic lustre.The streak is dark grey with a brownish tint.The tenacity is brittle and the fracture is splintery.There are probably two cleavages (possibly {100} and {010}).The Mohs hardness is about 5.The calculated density is 5.174 gcm -3 based upon the empirical formula.In reflected light, the mineral is bluish grey in colour with moderate bireflectance and slightly bluish grey to a lighter bluish grey pleochroism.Electron probe microanalyses provided (Mn 4+ 3.05 Cu 2+ 0.93 Zn 0.91 Al 0.05 ) 4.94 O 8 .Almagreraite is orthorhombic, Pmn2 1 , a = 5.7298(4), b = 4.9715(4), c = 9.3479(7) , V = 266.28(3) 3 and Z = 2.In the crystal structure (R 1 = 0.0297 for 423 I > 2 I reflections), Mn 4+ O 6 octahedra share edges forming an octahedral sheet