An image of a brown sphere with lines all over.
Geode from the Eldon House collection

Country of Origin: USA
Year: ca. 1910
Materials: Stone and crystal 

Geodes are spherical or oblong rocks filled or partially filled with minerals, most often quartz. The quartz can be massive, crystalline, or layered, which is a variety called agate. This rock was kept at the front door of Eldon House and used as a doorstop.