Works of "Research Collection"
Place Collected: Minerva #1 Mine
Place Collected: Landsverk No. 1
Place Collected: Keystone Trappe Rock Quarry
Place Collected: U.S. Borax Open Pit
Place Collected: Monroe Co.
Place Collected: Zaragoza
Place Collected: Blow River Area
Place Collected: southern Namibia
Place Collected: Minas Gerais