It doesn't get any more local than rammed earth, and done right, it doesn't get any more beautiful. The material is dirt cheap, but it's really labor intensive to work into all those beautiful layers. In fact, according to Designboom, the particular dirt on this site was too dark and too rich as a background for the art that was going into the building, so the builder, Rammed Earth Works, says it was blended with other materials to achieve the final color. The formula involved a blend of site soil with coarse sand, small gravel, crushed rhyolite, decomposed granite, and two different cements." (A little cement is added in most rammed earth walls to keep it from washing away in the rain and to get approved by the building inspectors)
The Windhover Contemplative Center at Stanford University "serves as a sanctuary for quiet contemplation amid the academic bustle." Designed by Aidlin Darling Design with lovely landscape by Andrea Cochran, a Stanford senior says "it is a very relaxing place to be and a welcome reprieve from the constant busyness of the Stanford campus. it’s nice to have a place to sit still and breathe deeply."
I think it owes a lot to Mies van der Rohe's Barcelona pavilion. Lots more photos in Designboom.