@misc{indiciaec81fff5961b5,
  title = {Virgin Valley opal district, Humboldt County, Nevada},
  author = {Mortimer Hay Staatz and Herman L. Bauer},
  year = {1951},
  doi = {10.3133/cir142},
  url = {https://pubs.usgs.gov/publication/cir142},
  note = {Source identifier: cir142}
}