During yesterday’s OHA walk around some of Oakland’s building stones, I was pleased to bring out an underappreciated aspect of this great city landmark.
The Kaiser Center, like City Hall, is one of Oakland’s signature buildings. When construction finished in 1960 the curving, T-shaped office tower was so iconic that Ansel Adams is said to have photographed it, presumably giving it the same sheen of grandeur he gave Half Dome. (I couldn’t find that image, although Rondal Partridge also photographed it, which is just as good.)
The photo above shows the butt-end of the 7-acre Kaiser Center complex, at Webster and 21st streets. In the foreground is the parking structure/commercial space that holds up the wonderful rooftop garden.
The Kaiser Center is famous for its extravagant use of glass and metal, specifically aluminum, Kaiser Aluminum’s principal product and a design element dictated by Henry J. Kaiser himself. But I spoke to the group about the third element that embraces the metal and glass in a gracious unity — the white stone cladding.
As you walk around the Center, the cladding appears pleasantly rough yet perfectly homogeneous. It’s not a veneer of solid stone, nor is it some kind of textured concrete. Neither is it painted. It’s an extraordinary material. After 55 years of weather, it still looks white and crisp and fresh.
Nearly all of the cladding is out of reach. Some panels touch the ground along the curving roadway behind the main tower, but that’s too hazardous even for your typical roadside-loving geologist. However, at the left edge of the photo is a little section of wall where the architects felt obliged to extend the cladding to the sidewalk. That’s the only safe place to examine it.
The backing is concrete, but the aggregate that makes up the face is a pure white stone. Steel scratches it, therefore it is not quartzite, which was my first guess. It has the frosty luster of a carbonate, but it doesn’t fizz under dilute hydrochloric acid (I always carry some). Therefore it is not ordinary limestone or marble. It’s something much less common: coarse-grained dolomite, a stone with its own place in Kaiser’s history.
Whereas limestone and marble consist of calcite (CaCO3), dolomite rock or dolostone consists of the mineral dolomite (CaMg(CO3)2), in which magnesium takes the place of half of the calcium. It has many industrial uses, and the Kaiser conglomerate has mined it in several different quarries.
During World War II, magnesium metal was in great demand, especially for aircraft. The supply of magnesium ore, magnesite (MgCO3), was very tight. (Magnesite was mined at this time south of Livermore, in Del Puerto Canyon.) Kaiser sought a way to produce magnesium metal from dolomite using the Hansgirg process, but the process was plagued with difficulties. The magnesium program was known as one of Kaiser’s biggest headaches.
Henry Kaiser was closely involved in the design of the Center — indeed, it’s said he intended to live there. One of his conceits was that the materials, as much as possible, should be supplied by Kaiser companies. His architect, the Los Angeles modernist Welton Becket, was noted for his use of natural stone cladding.
I imagine that Becket and Kaiser were pleased, each for his own reasons, to showcase the exceptionally pure dolomite from Permanente Metals’ large Natividad quarry, a few miles north of Salinas. I feel quite sure that’s what this is.
More reading:
“Looking Down on Creation” in The Monthly, Nov 2006
“Five Painterly Vistas from Kaiser Rooftop Garden” in The Urbanist, Mar 2011
The Natividad quarry (bottom of the page), at Quarries and Beyond
Oakland Geology 
18 July 2016 at 9:07 pm
So how does the dolomite stay so relatively clean when it’s so heavily textured?
[Good question. They must steam-clean it periodically. But it’s clearly built to last. You don’t see it crumbling onto the sidewalk.
Also, if you zoom in on the bottom image you’ll see a lot of grit. The underlying stone is so white that the dirt barely affects the color. — Andrew]
18 July 2016 at 9:05 pm
There are still large pics on the 2nd floor display area of the main building (along with some HJK tributes) and also the lobby off the roof garden in the former White House wing. I bet these are the ones you’re thinking of.
18 July 2016 at 11:47 am
Some of those Ansel Adams pictures used to be on display in the hallway that runs through the ground level of the parking garage, connecting the drug store to several other indoor establishments and terminating on the lakeside-edge of the parking garage, near the intersection with Harrison.
The photos included a number of images of the building and surrounding areas under construction, and were fascinating.
I think that I once saw some other pictures from that series, or perhaps some of the same ones, in an Adams exhibit at the Oakland Museum.
It’s also possible that the images I’m remembering were actually Rondal Partridge, or were even someone else entirely.
Unfortunately, I haven’t worked or spent much time in that part of Oakland in more than 10 years, so these memories are pretty flawed…