Wednesday, February 16, 2011

Seattle Stone: Lobby #2, Smith Tower onyx

In continuing my short tour of Seattle lobbies, I turn to what is one of the best known lobbies in the downtown area. Smith Tower is also one of Seattle’s more famous buildings. Opened on July 4, 1914, the 462-foot tall building was the tallest building west of Ohio at the time. Over the years, the mostly terra cotta clad edifice has borne the brunt of many incorrect claims. As a fine essay on the web site reports, it was never the fourth tallest building in the world, or even outside of New York.

Despite not meeting the aspirations of some, Smith Tower does sport a rather handsome lobby. Two stones dominate, onyx marble from Mexico and marble from Alaska. This post will focus on the Mexican rock.

Onyx is a notoriously confusing stone. True onyx is a variety of quartz. It is sometimes referred to as layered chalcedony or black-and-white agate. The onyx used as building stone is not made of quartz but of calcite and is known as onyx marble. Because such calcareous onyx became popular in the United States through stone quarried near Mexico City, it is also called Mexican onyx, as well, no matter its point of origin. Onyx marble used in ancient Rome and by early Egyptians usually came from Algeria. All onyx marble is popular because of the colorful layering and ability to be highly polished. Color variation depends on the amount of iron and manganese and their oxidation states in the deposits, which become layered as they accumulate in pools.

The Smith Tower onyx panels are from Baja California from an area known as El Marmol. Like all onyx marble, it formed layer by thin layer in springs, in this case cold water springs. Other onyx marbles form in hot springs, too. They can also form as stalactites and stalactites. First quarried around 1893, the El Marmol deposits are about 160 miles southeast of Ensenada and 15 miles from the east coast of the peninsula. (One additional note. After posting this blog, I was reminded that the onyx in Smith Tower is also called Pedrara Onyx, in reference to the company that owned the quarries.)

The Spring at El Marmol (from the Tacoma World web site)

El Marmol achieved a bit of fame for its onyx marble schoolhouse, which was supposedly the only all onyx place of education in the world. Apparently the stones were not polished and by at least the 1950s, the weathered stones were drab and brown. As you can see from this modern shot, it’s not in very good shape.

The schoolhouse at El Marmol (from Tacoma World web site)

When geologist George Perkins Merrill visited the Baja quarries in the early 1890s he found the deposits quite pleasing. “Nothing can be more fascinating to the lover of the beautiful in stones than this occurrence, where huge blocks of material of almost ideal soundness, with ever varying shades of color and veination lie everywhere exposed in countless numbers…The colors are peculiarly delicate, and there is a wonderful uniformity in quality…The rose color is, so far as my present knowledge goes, quite unique and wonderfully beautiful.

The quarry at El Marmol closed in the early 1960s. An article by naturalist Joseph Wood Krutch theorized that it was due to plastic. He wrote “As with so much that is coming in the world, there is a cheap substitute for something dearer and more beautiful.” Fortunately, we can still see the dear and beautiful at Smith Tower.
Next time, I will look at the Alaskan marble.

Wednesday, February 9, 2011

Seattle Stone: Lobby #1

I am starting a series looking at buildings in Seattle. I plan to focus initially on some lobbies that I have long liked. My first is the wonderful art deco Exchange Building. Ironically finished in 1929, the building, as the name suggests, was supposed to house the Northwest Commodities and Stock Exchange. Most of the elaborate motifs feature items that represented Washington state agriculture. It is a lovely building.

For many years, I have taken people to the building on my downtown building stone tour and focused on the exterior Morton Gneiss. If we went on a weekday, I would often go inside and show them the extravagant stone, although I had no clue where the stone originated.
Recently, I was showing Dave Tucker of Northwest Geology Field Trips around Seattle to help him put together a tour for a guidebook he is writing on regional geology. When we stopped at the Exchange Building, his excitement prompted me to try and find out a bit more about the stone. Here's what I learned.

The stone is quarried in Italy near the town of La Spezia, about 14 miles west of the legendary marble quarries of Carrara. The best quarries are on the Tino islands. Initially quarried in the first century and used in religious buildings, the Romans also employed it to pave roads (now that would be wicked cool to see) and in the Luni amphitheater at La Spezia. Quarrying ramped up again after World War II but has slowed down of late. The ancient name was Portovenere and the modern name is Portoro (from Porta oro), with varieties labeled Portoro a macchia larga (large-veined), Portoro di Prima (the best variety), and Portoro a macchia fine (thin-veined).

Geologically, it is part of the vast sedimentary rocks of the Tuscan nappe. The Late Triassic Portoro Limestone is an aragonite mud deposited on a shallow carbonate platform. It is up to 260 feet and consists of black calcite with alternating layers of mixed dolomite and calcite. The complex folding and reworking of the micritic limestone during Miocene deformation, which also metamorphosed the Carrara marble, produced the distinctive and beautiful stylolitic veining that characterizes the stone. Four- to eight-inch-wide shear zones separate undeformed layers up to eight inches thick.
Sorry for the bad coloring. This stone is black. The purple is light reflected from Cherry wood paneling.
The black coloring primarily comes from small amounts of organics in anaerobic environments. Limonite and sulfides produce the yellow banding with dolomite mosaics and hematite forming more violet veins.
The building architect, John Graham Sr., did a splendid job of bookmatching the Portoro panels. He also incorporated Italian travertine and some sort of purple brecciated stone, which I know nothing about. Someday I hope to figure out that part of the story.
Curiously, the Portoro is a stone of warm places, such as northern Africa and Sicily. When weathered, it loses its brilliance and appears "irreversibly opaque, whitened and corroded," according to one study of it. You can see this in Seattle at the entrance to Shucker's Restaurant on 4th Avenue, just north of Seneca.

Next up will be the elegant lobby of the Smith Tower.

Wednesday, February 2, 2011

Louis Kahn and Travertine

Last night, I watched a fascinating documentary about the iconoclastic architect Louis Kahn. As the title implies, My Architect: A Son's Journey, follows Kahn's son Nathaniel as he attempts to discover the father he didn't know. Kahn was one of the greatest and most complex architects of the twentieth century. He is best known for his work in the United States, which includes the Kimball Art Museum in Dallas and the Salk Institute in La Jolla. He also designed astounding buildings in Bangladesh and India. What he was less known for was that he had three families, one with his wife and two through long-term affairs. All three produced children. The movie is well worth watching not only for Kahn's fascinating life but also for his stunning architecture.

What I like best about his work is his use of geometric shapes. He punctuates his walls with angles and arches and circles, allowing an ever changing interplay of light and shadow. Each design brings the buildings to life as they change shape throughout the day. His use of geometric shapes also connects his buildings to the landscape, not necessarily in an organic way, but in a way that continues the weaving of the ephemeral and the permanent.

And finally, Kahn appears to have been quite the fan of travertine. His use of it at the Salk Institute foreshadows and seems to have inspired Richard Meier's use of the stone at the Getty Museum. Below are some photos I found on the web that to me are some of the most notable uses of travertine. I hope you'll agree.
Kimball Art Museum (from the Southern Live Oak blog)
Kimball Art Museum detail (from flickr)
Salk Institute (from Daily Icon)
Salk Institute details (from Daily Icon)
Salk Institute seats (from Premier Green)
Yale Museum for British Art (from flickr)