This glass exhibition space is a Philip Johnson designed annex to the main Dumbarton Oaks Georgetown mansion.
(July 14, 2011) This might be a replica of the original. Jade is green stone - more like the weblink photo. Also, contrary to the weblink, this is probably not the maize god - who in Mayan art is usually a depicted as beautiful youth.; - this is probably a representation of a Xibalban or death-lord.
(July 24, 2011) This could also be a representation of the charismatic serpent deity Quetzalcoatl; or Gucumatz- in the Mayan "Popul Vuh."