It's a phenolic laminate

by Miles , CIVITATES AMERICAE, Friday, March 13, 2015, 14:48 (3483 days ago) @ StoneWolf

G10 is a "shorthand" of the material specifications

Here's a spec sheet:

http://composite-laminates.com/phenolics-technical-data.htm#.VQM-ojhFBYU