Physicists discovered in 2013 the world's first naturally occurring topological insulator, which can be mined from the earth's crust.
Notes on verification
Confirmed by multiple independent sources including a peer-reviewed publication (Nano Letters) and science news outlets reporting on the discovery of natural topological insulator mineral (kawazulite-related material).
Sources
- Physicists Discover World's First Naturally Occurring Topological Insulator (technologyreview.com)
- https://pubmed.ncbi.nlm.nih.gov/23438015/ (pubmed.ncbi.nlm.nih.gov)
- https://pubs.acs.org/doi/abs/10.1021/nl304583m (pubs.acs.org)