There are no ages for Sylvite at Lewis Pit, Hycroft Mine (Crofoot-Lewis Mine; Standard Slag Mine; Crofoot Gold Project; Crofoot Project; Crofoot Mine; Lewis Mine; Hycroft-Lewis Mine; Brimstone; Gap; Graveyard [Boneyard]; North Pit; South Central Pit; South Extension Pit; Peninsula), Sulphur, Sulphur District, Humboldt Co., Nevada, USA