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Sulfate

Sejkoraite-(Y)

Y₂[(UO₂)₈O₆(SO₄)₄(OH)₂]·26H₂O
Hardness2
Crystal systemTriclinic
ClassSulfate
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Sejkoraite-(Y)

Sejkoraite-(Y) is an IMA-recognized mineral species in the sulfate class, with the chemical formula Y₂[(UO₂)₈O₆(SO₄)₄(OH)₂]·26H₂O.

It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Zippeite structural group.

Key properties: Mohs hardness 2; specific gravity 4.04; Pale yellow-to-yellow streak; Strong vitreous luster; optically biaxial.

IMA symbol Sej-Y, IMA status: approved, named in 2009.

Coating surfaces of relic primary minerals: uraninite, chalcopyrite, and tennantite, altered in an acidic oxidizing environment.

It is found associated with Pseudojohannite, rabejacite, uranopilite, zippeite, gypsum.

The mineral was named to honor Jiří Sejkora, National Museum, Prague, Czech Republic, for his contributions to the study of uranyl-containing phases.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more S minerals or help write this entry.