Yellowish-green to black autunite – tabular crystal – Daybreak Mine, Spokane, Washington, USA
The UO22+ peaks at 19869 (503.3), 19048 (525), 18228 (548.6), 17406 (548.6), 16584 (548.6), 15763 (548.6) cm-1 (nm) yield a Δk=820±1 cm-1 at room temperature.