No new structure in Washington is so visible from so far or from so many different points of view as One Franklin Square, a behemoth office building with two hexagonal, gold-tipped towers. These glint wonderfully when touched by the southern sun and, dramatically bottom-lit, they glow romantically at night.

One local photographer who has shot many a building over the decades has been intrigued by the sight since the tower caps were put in place last fall. "It's not like Washington," he said. "It's like New York." And so it is. To see these splendid pinnacles peeking above the trees in Franklin Square is akin to glancing toward Fifth Avenue from New York's Central Park.

This elevating, urbane image is exactly what the architects had in mind. With the exception of the towers, the building is big in the recent Washington mold, longer along its K Street facade than any elevation of the FBI Building, according to Graham Davidson of the local Hartman-Cox firm. "The challenge was to design a horizontal building made up of vertical pieces," explains partner George Hartman.

One Franklin Square is the third Hartman-Cox commercial project to be completed in the downtown area in the past year. (The others -- Market Square at Pennsylvania Avenue and Eighth Street NW, and Pennsylvania Plaza at Indiana and Sixth NW -- have been reviewed in this column as they opened.) Each is different from the others. Each takes something from the city's history and from the specific location and transforms it into a new thing.

The firm's motto might be: Take what the site offers, and take it as far as it can go. It is a responsive, responsible formula for building in the city, capable of many subtle mutations. It is possible to have certain reservations about the results -- as I do, concerning One Franklin Square -- and still appreciate and admire the formidable skill and crisp intellectual energy of the enterprise.

What this site offered was an extraordinary amount of urban turf, taking up very nearly the whole northern edge of Franklin Square between 13th and 14th streets NW, and quite an interesting architectural environment. Adjacent is the exotic Almas Temple, which was moved and restored as part of the project. Close by are the Hamilton and Tower buildings, two accomplished limestone variations on pre-World War II beaux-arts themes; the castellated 19th-century Franklin School; Philip Johnson's new building across the park, an authoritative neoclassical reprise; and a number of ribbon-window office buildings dating mostly from the 1960s and 1970s. (These last stand as more or less regrettable examples of what not to do.)

What the new Hartman-Cox building does in fine fashion is to complete the architectural framework of downtown's most spacious park. The urban design goal, as Hartman said, was to break up the structure's potentially off-putting horizontal bulk by emphasizing vertical dimensions. The architectural theme of stepped-back volumes, recalling the profile of New York buildings of the '20s and '30s, followed quite naturally.

The result is in most respects an adroit and impressive exercise. The symmetry of the building is august but not boring. The twin towers are not quixotic addenda to the building top, placed there with the sole intention of enlivening the city's skyline (though this they most certainly do). Rather, they are succinct architectural forms, defined by projecting piers that begin at the base of the building.

Each clearly announces an entrance -- as is customary in Washington buildings of such size, this one has two separate elevator and service cores -- and each is framed by a wing whose actual heft is visually diminished by projecting bays and setbacks. Obvious effort was made to articulate the light-pink granite facade, to give it depth and shadow lines. Though not as pronounced as, say, that of the Franklin School, the sequence of bays, balconies, piers, pilasters and windows is persuasive in its own, abstracted way.

Despite the fact that the stone skin is but three-fourths of an inch thick, mounted on precast concrete panels, care was taken to create deep reveals between the thin sheets of granite. Hence, the overall impression is of a weighty building, made of stone. Even so, the amount of transparency is equal at least to that of the modernist buildings nearby. But the rhythm of the paired windows here is definitively vertical. They zoom upward, and with them so does the viewer's eye.

The ample reward is those pewter-toned towers with their gilded pinnacles, quite the most extraordinary gestures made on the Washington skyline in many a moon. The building is in accord with the height law, which dictates a top of 130 feet in this location. But the law sets no limit on turrets, spires, minarets and so on above this line (so long as they remain functionally useless), and Hartman-Cox extended this intentional loophole for all it was worth. At the tippy top, these babies rise 90 feet above the building line, a proportion that feels right, given the bulk of the building below. It was a daring and a proper thing to do: The towers have changed the image of Franklin Square for good.

Unfortunately, parts of this design don't live up to the high -- indeed, the exhilarating -- standard set by its overall form. In part, perhaps, this is the unhappy norm for buildings as big as this one. Almost always, the ground floors are of an off-putting scale, and they stretch along interminably. The lack of strong retail focus in the neighborhood contributes to the effect. But it's also an important question of detailing. That this design brings older New York models to mind doesn't automatically mean that it is as good as the best.

All of these sophisticated urban design stratagems can -- and did, here -- add up to a certain indeterminate quality, a building of no certifiable age. It recalls deco, and streamlined moderne, and skyscraper modern, but it isn't any of these. There is an absence of ornamental follow-through. In grillwork panels, chandeliers and elevator doors the architects tried to create a consistent theme, but it seems a halfhearted effort. In the lobbies, for instance, a curious change of mind seems to have taken place: They're vaguely neoclassical, but why? The net effect is somewhat dispiriting -- the closer one gets to One Franklin Square, the less exciting it is.

Almas Temple, on the other hand, is a real treat close up, as it has been from the day it was erected more than 60 years ago for the Ancient Arabic Order of the Nobles of the Mystic Shrine. The Shriners, that is. It is very nice to have the building (and the Shriners) so visibly back. The entire facade was dismantled tile by tile, moved about 100 feet westward, and reconstituted, an enlightened tactic typical of Washington's responsible urbanism at its best.

Here, it saved a curious little jewel of a building that more than ever is a needed punctuation mark on the block. Restoration work was confined to the facade; behind it there are a couple of floors of office space used by IBM, the chief tenant of One Franklin Square, and a whole new setup for the Shriners. This includes a lobby with a nifty Islamic dome, a restaurant (the Sphinx Club) open to the public, a bar (the Fez Room) and a spacious banquet hall located in the basement. The Shriners should give tours -- the drop screens behind the banquet hall podium are something to see.

The list of well-deserved credits is predictably long. Hartman-Cox did the basic architecture and urban design work for Prentiss Properties, the Dallas-based developer. The firm of Dewberry and Davis was associate architect, producing the working drawings for One Franklin Square. Oehrlein Associates were in charge of the Almas Temple facade preservation. John C. Samperton Associates planned the interior spaces for the Shriners; Swanke Hayden & Connell conceived the Islamic-inspired interior design.