Black Diamond

The Black Diamond is the waterfront extension of the Royal Danish Library on Slotsholmen, in central Copenhagen. Its name comes from its skin: 2,500 square metres of polished black granite, a stone known as Absolute Black, quarried in Zimbabwe and cut and polished in Italy. Each slab weighs 75 kilograms.

The shape is a box pushed out of true. It leans towards the harbour and to one side, and widens slightly as it rises. A glazed cleft splits the front in two and lets daylight into a central atrium, while a band of glass along the ground floor is meant to make the block seem to float on the water.

An international competition in the early 1990s drew 178 firms, and Schmidt Hammer Lassen won it in 1993. Construction began in 1995 and cost DKK 465 million. The building opened to the public on 15 September 1999, named by the culture minister of the day, Jytte Hilden. It was the first of a series of large cultural buildings along Copenhagen’s waterfront.

Inside, the dark exterior gives way to a bright atrium with wavy balconies. The extension added 21,500 square metres: one reading room became six, and 96 study seats became 474. Bridges over the busy Christians Brygge join it to the old building. This is not an open-shelf library. Readers order books online or on a slip and collect them the next day, so the catalogue is the way in.

The building also does what we describe in the modern library: more than books. The Queen’s Hall seats 600, with acoustics that adjust between classical music and jazz. And every day at 1 pm a piece of about three minutes from Katalog, by the composer Fuzzy, plays through the atrium. There is a new one each week of the year, each inspired by a treasure in the collection.