Sturmanite - Ca₆Fe³⁺₂(SO₄)_2.5[B(OH)₄](OH)₁₂·25H₂O

Habit: Bright yellow to amber. Dipyramidal tabular to elongated hexagonal crystals; may be stacked in parallel aggregates. Greasy luster on fracture faces; transparent to translucent. Yellow white streak.

Environment: An uncommon secondary mineral in cavities in metamorphosed bedded manganese deposits.

Etymology: Named for B. Darko Sturman (b. 1937), a mineralogist at the Royal Ontario Museum, Toronto.