Technogenic steklite, KAl(SO₄ )₂, and unnamed mineral phase (K,Na)₃ Na₃ (Fe,Al)₂ (SO₄ )₆ from burnt dumps of the Chelyabinsk Coal Basin have been investigated by single-crystal X-ray diffraction and electron microprobe analysis. Steklite is trigonal, space group P3, a = 4.7277(3), c = 7.9871(5) Å, V = 154.60(2) ų . The crystal structure was refined to R₁ = 0.026 (wR₂ = 0.068). It is based upon the [Al(SO₄ )₂ ]⁻ layers formed by corner sharing of SO₄ tetrahedra and AlO₆ polyhedra. The anionic [Al(SO₄ )₂ ]⁻ layers are parallel to the (001) plane and linked via interlayer K⁺ ions. The regular octahedral coordination of Al is observed that distinguishes technogenic steklite from that found in Tolbachik fumaroles. The (K,Na)₃ Na₃ (Fe,Al)₂ (SO₄ )₆ phase is trigonal, space group R3, a = 13.932(2), c = 17.992(2) Å, V = 3024.4(7) ų, R₁ = 0.073 (wR₂ = 0.108). The crystal structure is based upon the anionic chains [(Fe,Al)(SO₄ )₃ ]³⁻ running parallel to the c axis and interconnected via K⁺ and Na⁺ ions. There are no known minerals or synthetic compounds isotypic to (K,Na)₃ Na₃ (Fe,Al)₂ (SO₄ )₆, due to the presence of separate K and Na sites in its structure.