The building’s skin, a double skin whose lightweight, impalpable surface seems to take shape gradually before our eyes has become an identifying architectural feature over the last decade, the focus of much thought and many projects by some of the most interesting talents on the international scene. The building’s skin embraces essential functions with effortless ease, contributing to the modernist mission of freeing up the body of the building to create transparent spaces suitable for any use. As a result, the outer skin has become a piece of hardware, receiving and storing an incessant flow of information, its embedded technology becoming more sophisticated by the day. The building’s skin fulfils another, increasingly important function of contemporary architecture: to convey the architectural message and in turn, project the image of the client and the client’s brand. As Venturi prophesized, to justify its raison d’être, architecture is turning buildings into advertising hoardings. And to do so it makes increasing use of ever more sophisticated and elegant means. In going down this road though, architecture is shifting its centre of gravity dangerously close to that line beyond which a building risks becoming an ephemeral entity subject to the whims of fashion, taste and marketing. The skin is an interface projecting a ceaseless message, architecture an ancient medium in a period of flux and constant transition. These were my thoughts as I looked over the project for the small De Beers building in Los Angeles designed by Antonio Citterio with the assistance of master craftsman Stefano Ronchetti. The building concept, especially its striking façade sprung from a previous project for the same client: the 2001 refurbishment of the London store of De Beers, perhaps the most important diamond dealer in the world with a particularly exclusive clientele. The Citterio practice had based the London makeover on two elements common to both the location and the client: sophisticated elegance and the brilliance of glinting diamonds. The wide use of Macassar ebony on the floors and for the display cabinets is offset by a series of sandwich partition walls of crystal glass panels engraved with geometrical grid patterns, and lit internally by embedded optical fibres. This was the matrix for the De Beers brief on Rodeo Drive, Los Angeles. And the point of departure of a whole new research programme currently being developed by the Citterio practice. It also signals Citterio’s shift over the last ten years from the world of design to interior décor and then to architecture. This is a natural transition accomplished by many of the greats of Italian design at the turn of the last century. As designers, they all share a common background and have a common approach to the architectural project. Their intuition of how an object should take physical shape in space is brought into existence with the obsessive attention to minutia born of profound familiarity with the best tradition of Italian industrial design. To this Citterio adds his own very specialist personality. He comes from the school that combines the rigorous, neoclassic traditions of Lombardy with the clean lines of 20th century rationalism. He is steeped in the values of an austere yet elegant bourgeoisie for which technology is the means of satisfying man’s need, and materials are meant to create essential forms that will deliver simple wellbeing and withstand the test of time. The diminutive size of the Rodeo Drive building is countered by two inter-related features: the façade and its continuity of line from the ground floor to the top-floor covered terrace. The crystal glass partition walls of the London store are here placed on the outside. The façade is the building’s logo, a suitably bold statement for a city like Los Angeles where glamour and wealth are openly flaunted. The building is cloaked in a double skin consisting of stainless steel sheets, each honed by hand, behind a façade of crystal glass (engraved with regular geometrical patterns) mounted on a square frame of grey steel that boxes the entire building right up to the roof. The project makes uses of a resource in constant supply in California: the sun. The light reflects off the steel sheets onto the crystal glass walls creating a vibrant luminosity that varies as the day proceeds. It is an “atmospheric” building with a sartorial façade. The De Beers store in LA is a money’s-no-object building right to the core. All the component parts were developed and pre-assembly outside Milan by Marzorati Ronchetti, the metalworking equivalent of international haute couture, and then transported to Los Angeles for installation. The building is made to appear larger thanks to a few smart expedients: the horizontal emphasis of the mullion and transom steel frame supporting the crystal glass panels; the fold given to the grid at the top of the façade making it appear to wrap around the building; the way the façade extends beyond the top of the building giving a glimpse of the covered terrace; and the use of natural and artificial light to vary the light reflectance on the façade. The spin-off from Citterio’s LA experience is evident in his competition entry for a hotel complex at Milan’s new trade fair, and in a hotel currently going up in Osaka. In both cases the façades have a vibrant density. In the Milan project, the mix of steel, ceramic and crystal glass lends consistency to a wafer thin building; in the Osaka hotel, the façade envelopes the services plant. The outer perimeter of buildings has now become a place of cutting edge experimentation. Is this one of the inevitable directions being taken by contemporary architecture? Luca Molinari