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(mineralogy) A rare triclinic carbonate mineral, usually white, lemon yellow, or amber, and sometimes translucent.

Weloganite – Carbonate mineral – Na₂(Sr,Ca)₃Zr(CO₃)₆·3H₂O – Wlg – 5.CC.05 – 15.3.4.4 – Triclinic – Pedial (1) – P1 – A = 8.966 Å, b = 8.98 Å – C = 6.73 Å; α = 102.72° – Β = 116.65°, γ = 60.06°; Z = 1 – 814.16 g/mol – Yellow, pale yellow, amber, tan, white – Roughly hexagonal, tapering crystals, pseudorhombohedral – About [103] repeated at 120 degrees – Perfect on pseudo {0001} – Conchoidal – 3½ – Vitreous – White – Translucent – 3.20–3.22 – Biaxial (−) – Nα = 1.558 nβ = 1.646 nγ = 1.640 – Δ = 0.082 – Measured: 15° – Weak – Pyroelectric. triboluminescent.