The Nature of Diamonds

  • George E. Harlow
Cambridge University Press, $75, £55 (hbk); $29.95, £19.95 (pbk

Some three billion years ago, in the Earth's mantle, the hardest natural substance in the world was formed and stored. Kimberlite and lamproite magmas later brought it to the surface. Now researchers use it for creating high-pressure cells to investigate planetary interiors and dense matter, mimic the Earth's core or produce solid hydrogen.

The scientific story of the diamond is one facet of a new exhibition at the American Museum of Natural History in New York, “The Nature of Diamonds,” which runs until 26 April 1998. The exhibition is accompanied by a book of the same name written by the museum's curator of gems and minerals.

Transliterated from the Greek ‘adamao’ meaning ‘I tame’ or ‘I subdue’, the stone's name has become connected with power and strength, and these associations are explored in cultural and historical facets of the exhibition. These sections lead on to a stunning array of jewels from the Middle Ages to the twentieth century, including the Incomparable (pictured), weighing 407.48 carats — the third-largest cut diamond in the world.

But the exhibition offers plenty for interested scientists to get their teeth into. Interactive displays illustrate the main properties of diamond, such as its hardness, refractive index, conductivity and colour — the blue diamond, for example, gets its colour from minute amounts of boron.

The way diamonds are formed is explained in detail, with displays taking the observer through their history.

The use of diamond in research is also highlighted. As well as the diamond anvil cell, whereby two stones are squeezed together to create pressures of up to 4.5 million atmospheres, diamond is also a universal cutting tool and, because of its apparent iciness — heat-conducting ability — is used in electronics to manage heat.

For both science and spectacle, this exhibition is a real gem.