“Natural pocket of acicular natrolite growing in pillow basalt at the Wren quarry in Benton County, Oregon, USA. Pocket is approximately 10 inches (25.5 cm) across. My apologies for the dirt and rock crumbs, but I was clinging to a crumbly rock wall 20 feet up with an expensive digicam in hand. ;) Photo courtesy of Aaron Wiltsey.”
Aaron Wiltsey - 22nd August 2005