. Jalbum 8.13 Rocks, minerals, and geology in the north hills and Claremont Canyon watershed. This album will grow only as pictures with full identifications are submitted by viewers. slides/Interesting Mineral Sample 8_9_07.html# Sun, 02 Jan 2011 14:41:13 -0800 Interesting chert sample at Pacifica transmitter site, Oakland, CA on Aug. 9, 2007. Photo by Bob Nelson. Comments by Doris Sloan, emerita Prof. of Geology at UC Berkeley: "An excellent and interesting example of the weathering of rock. The brown coating is iron oxide. It is the result of fluid rich in dissolved iron migrating through the fractures in bedrock (that is, rock in place in the ground), and leaching into the rock. Sometimes when you see this, it looks like the iron dissolved out of the piece of rock itself and leached out to the edge. But in this one, it looks to me as if the iron was picked up in other rocks, dissolved in water that then flowed through the chert (or whatever the rock is)." Interesting chert sample at Pacifica transmitter site, Oakland, CA on Aug. 9, 2007. Photo by Bob Nelson. Comments by Doris Sloan, emerita Prof. of Geology at UC Berkeley: "An excellent and interesting example of the weathering of rock. The brown coating is iron oxide. It is the result of fluid rich in dissolved iron migrating through the fractures in bedrock (that is, rock in place in the ground), and leaching into the rock. Sometimes when you see this, it looks like the iron dissolved out of the piece of rock itself and leached out to the edge. But in this one, it looks to me as if the iron was picked up in other rocks, dissolved in water that then flowed through the chert (or whatever the rock is)." slides/Interesting Mineral Sample 8_9_07.jpg slides/Chert-1042.html# Sun, 02 Jan 2011 14:41:13 -0800 Chert wall with monkeyflower in Claremont Canyon, Oakland, CA on June 20, 2009. Photo by Marilyn Goldhaber. Chert wall with monkeyflower in Claremont Canyon, Oakland, CA on June 20, 2009. Photo by Marilyn Goldhaber. slides/Chert-1042.jpg slides/Chert-1043.html# Sun, 02 Jan 2011 14:41:13 -0800 Chert wall closeup in Claremont Canyon, Oakland, CA on June 20, 2009. Photo by Marilyn Goldhaber. Chert wall closeup in Claremont Canyon, Oakland, CA on June 20, 2009. Photo by Marilyn Goldhaber. slides/Chert-1043.jpg slides/Chert-1044.html# Sun, 02 Jan 2011 14:41:13 -0800 Chert wall in Claremont Canyon, Oakland, CA on June 20, 2009. Photo by Marilyn Goldhaber. Chert wall in Claremont Canyon, Oakland, CA on June 20, 2009. Photo by Marilyn Goldhaber. slides/Chert-1044.jpg slides/Chert-MG30.html# Sun, 02 Jan 2011 14:41:13 -0800 Claremont chert formation with lupine on Claremont Avenue, Oakland, CA on March 11, 2004, by Marilyn Goldhaber. Claremont chert formation with lupine on Claremont Avenue, Oakland, CA on March 11, 2004, by Marilyn Goldhaber. slides/Chert-MG30.jpg slides/Rock-091101-10.html# Sun, 02 Jan 2011 14:41:13 -0800 Unidentified rock on south base of spiral knob, Ridge Trail above Claremont Canyon, Oakland, CA on Nov. 1, 2009. Photo by Ken Cheetham. Unidentified rock on south base of spiral knob, Ridge Trail above Claremont Canyon, Oakland, CA on Nov. 1, 2009. Photo by Ken Cheetham. slides/Rock-091101-10.jpg