Mountain View Cemetery is a fun place for geology. Not only are there the untouched hillsides and the knockers of local bedrock, but the monuments themselves are displays of fine stone from around the world. On my last visit, though, this one caught my eye.
It’s an example of the oldest stone in the United States, the Morton Gneiss from southwestern Minnesota. I mentioned it a few weeks ago in a KQED Quest Science Blogs post before finding this specimen. Touching it will put you in contact with something 3,524 million years old, more than three-fourths of the planet’s age.
Let me take this opportunity to plug Michael Colbruno’s blog about the people in the cemetery. He calls it “Lives of the Dead: Mountain View Cemetery in Oakland,” but I still think of it by its original (non-SEO-friendly) name “Mountain View People.”
Oakland Geology 
25 April 2012 at 8:21 pm
Scientifically-trained people will likely disagree; nevertheless — it seems to me that no one can really comprehend so long a time span. I was awakened to this by a tour guide at Old York. We tourists were struggling to grasp the expanse of human history there (prehistory, Vikings, medieval battlements, cathedrals) and he pointed out a fossil in a stone that was part of a castle. “That’s about 25 million years old”, he said. “You can’t grasp that.” In the context of day by day life and history, he was right.