Rock is transparent as the sky, and glows like a thought with immortal life.

"I spring to my feet, crying: 'Heavens and earth!  Rock is not light, not heavy, but is transparent and unfathomable as the sky itself.  Every pore gushes, glows like a thought with immortal life, . . . the whole rocky picture seemingly translucent as if lighted from within by its own internal light!' "

The Contemplative John Muir, pp. 77-78. 

Photo: Sunlight shines through a screen of rain, with White Loco growing on the hillside in the foreground, Reservoir Ridge Natural Area, CO, April 23, 2012.  For a look at my book: "The Contemplative John Muir," go  here.