A geohashing marker, to serve for http://www.geohashing.org - it is meant to be stuck into the earth at the hash point. Or into whatever you find on location.
This thing is derived from crox' coin, which uses dawidi's tracing of the geohashing logo, which derives from the xkcd.com webcomic. Crox' coin is inspired by my own tin cast coins. This makes the license a bit of a mess - the xkcd comic is CC-BY-NC, which is why I am publishing it as such. It may be that the geohashing logo is actually under public domain.
Print (preferrably in biodegradable PLA), sharpen the pin with a knife.
Go geohashing! Plant marker.
You may label the reverse with a QR code or URL of your expedition page.
Marked as work in progress, as I am going to alter the shape of the pin a bit, to make it more printable. Currently, the sharp point does not stick very well.