This sample of native (naturally occurring) arsenic is from the Burraton Coombe Quarry, St. Stephen-by-Saltash, Cornwall, in the UK.
It happened to arrive in my mailbox on the very day Oliver Sacks was visiting the Periodic Table Table, so we got to open it together.
Source: Andrew Goodall
Contributor: Andrew Goodall
Acquired: 12 November, 2002