Diamonds tend to unleash the dark, avaricious side of human nature. In their presence, people have been known to take leave of their senses. But geology Professor Stephen Haggerty is at his scholarly best around the scandalous carbon crystals. Let others haggle and snipe over the price, the pursuit, the vagaries of the market; they can covet their priceless tiaras and commandeer the politics of whole nations in the name of greed. The real riches, says Haggerty, lie in the light these “natural antiques” can shed on the tumultuous, often elusive story of our planet’s evolution.
“Diamonds are a window into the deep earth,” Haggerty is fond of saying, and he has devoted much of his career to peering through that window trying to make geological sense of what he sees. Diamonds are just part of his far-reaching expertise, which ranges from economic geology (his work in the field earned him Britain’s Cullis Testimonial Medal in 1964) to rock magnetism to electron microanalysis. A Royal School of Mines graduate and former Carnegie Fellow, Haggerty has described seven new minerals. His doctoral thesis at the University of London’s Imperial College earned him the Judd Prize for research. Haggertyite is not the name of a disciple but a mineral christened recently in his honor. He labored to decipher the origins of the early solar system through studies of the Allende meteorite and he helped to sketch a geological profile of lunar rock samples harvested by the Apollo II astronauts. He has studied nuclear waste disposal and served as principal investigator in MAGSAT, the Earth-orbiting magnetometer satellite experiment. At UMass he established an electron microanalytical facility for mineral study.
Still, Haggerty’s name has come to be synonymous with diamonds. A rock from the moon may be quite consequential, but diamonds are — well, just try to imagine it — ordinary carbon atoms squeezed into crystals billions of years ago in the infernally hot, dense mantle more than 100 miles beneath the earth’s surface. To get to the places where mere mortals find them, the rocks had to ride volcanic eruptions like bullets through a gun barrel at 1,000 miles per hour to the earth’s crust. There they slumbered for 100 million to 1.1 billion years until man began to blast away at them or scoop them from riverbeds, until the time when the DeBeers family convinced us the gems are a prerequisite to marital bliss. Mined for nearly four millennia, diamonds are so precious that diamond mines are famously immaculate and the tiniest crystals are salvaged by pouring the dust-like mine sweepings over surfaces coated with grease, to which the crystals adhere. Haggerty has done this operation in the bush, in a crude fashion involving a kind of mambo on the part of the holders of a table slathered in car grease, and describes the magical beauty of a table surface en-crusted with shimmering diamonds. Though his interest is scientific, Haggerty is happy to indulge a lay person with descriptions of the treasures he has seen, and he’s accustomed to answering people’s timid inquiries about the integrity of their own jewelry.
These “natural antiques”
shed light on the tumultuous,
often elusive story of our
Haggerty himself sports nary a studded cufflink nor pinky ring. A pleasantly rumpled man with warm, deep-set eyes, he speaks in meticulous, staccato rhythms as if reciting poetry. The lilt and cadence of his speech are informed by both his native South Africa, where he was born 30 miles from the Premier diamond mines, and long tenure in England. Haggerty could pass himself off as someone from Auckland, Brisbane, Oxfordshire or Gander, which comes in handy in his frequent, far-flung and often risky travels. A decorative or industrial diamond’s journey to Zale’s, Tiffany, General Electric or Elizabeth Taylor’s ring finger often begins in some of the world’s most inhospitable and acrimonious corners, and so Haggerty’s science has found him stranded in a Monrovia hotel on the dawn of a violent 1980 civil war in Liberia, eating what he feared might be his last meal. He’s been subject to harassment, suspicion and surveillance — not long ago he was patronized and misled by the very same Syrian government agents who had invited him to their country. “Diamonds,” he declares, “bring out the worst in people.”
Diamond deposits and working mines have lured Haggerty to the nether reaches of the Siberian permafrost, where he celebrated the Fourth of July in a blizzard, and the wilds of Brazil’s Amazon basin. He has worked in Mali, Senegal, Sierra Leone and the Ivory Coast in west Africa and his expertise has taken him to China, Finland, Iceland and southern India. He is at home in the bush, has logged untold miles in the dusty confines of wheezing Land Rovers, and is known to don unconventional hats. So it was only a matter of time before colleagues jokingly referred to Haggerty as “the University’s Indiana Jones.” The nickname stuck, though mention of it seems to embarrass Haggerty, who gives me a withering look and says, “oh, that.”
His global exploits notwithstanding, Haggerty in the flesh is nothing like the cartoonish, swashbuckling Harrison Ford character. Well, yes, he did drag a sack of black diamonds through the Liberian crossfire and pleaded with American embassy officials there to grant the rocks temporary asylum. His countrymen were reluctant, but Haggerty prevailed. (Getting the rocks home was the real ordeal.) But Haggerty describes himself as a cautious man, scientist by occupation and adventurer by occupational hazard, intent on getting the goods while keeping himself alive and in one piece. For another, his exploits are played out in the company of sturdy graduate students and colleagues rather than spies, roving opportunists or Kate Capshaw. Though he admits it is necessary, on occasion, to bite his tongue and “dance with the devil” to be near the work he loves, Haggerty is an outspoken supporter of human rights and follows developments closely and hopefully in the regimes that have been his dancing partners. But Haggerty’s most un-Hollywood attribute is his enthusiasm about his own backyard. Here is a man who seems always to have just returned from some exotic tropical or sub-Saharan locale, waxing poetic over a pre-Cambrian outcropping in Hadley. “People always ask me how I feel about my travels,” says Haggerty. “And I tell them the best adventure is coming home.”
I visit with Haggerty in his rustic Morrill laboratory, a space he wears like an old sweater. What appears to the casual observer to be random piles of rubble are samples with which Haggerty is so intimate he occasionally leaps out of his chair and returns within seconds with a rock that precisely illustrates this or that geological point, and he defers to the microscope as often as some men reach for their reading glasses.
A native of South Africa’s high veldt who became an American citizen many years ago, he is entranced by the geology of his adopted nation and particularly of western Massachusetts. “At first I was worried I’d be academically isolated, that colleagues wouldn’t want to travel here,” says Haggerty, who joined the faculty in 1971, after a stint at the Geophysical Laboratory in Washington, D.C. “But that proved not to be true — this area is a great natural laboratory and a rich playground for the geosciences,” he says. That’s one reason Haggerty derives such pleasure from teaching a mineralogy course for non-majors. He is intent on startling students into an appreciation of the earth’s tempestuous history, and the ways in which its upheavals are chronicled so candidly in the land before the students’ eyes.
Haggerty’s fascination with minerals found its first outlet when he was only 19 and left Africa to work as an exploration assistant for a mining company in the wilds of Canada’s James Bay. In Haggerty’s presence the use of “rock” or “stone” as a euphemism for lifelessness seems profoundly inaccurate. Rocks are dynamic and packed with drama, records of the earth’s eternal shifting, folding, cracking, exploding in hot lava or being forever sculpted and transported by water and ice. They attest to an earth on which Africa and South America formed a single land mass, an earth shaken and rattled, boiled and cooled, frozen and thawed, even pelted with masses from outer space.
When I ask Haggerty about his current research, he places a few raw specimens in my hand. They are diamonds, sized at about 53 carats a piece. (A carat is a unit of weight, with about 140 equaling an ounce.) But I never would have recognized them. They are black diamonds and I could easily have mistaken them for worthless hunks of gravel. Although they couldn’t be more ordinary looking, geologically speaking these rocks couldn’t be more extraordinary, explains Haggerty, who has played a major role in a scholarly debate over the black diamonds’ origin. There is nothing on the planet remotely like them. Named carbonados by the Brazilians who first discovered them in 1840, black diamonds are found almost exclusively in Brazil and the Central African Republic, a country north of Zaire nestled between Chad and the Sudan.
Why the fascination with carbonados? They are exceedingly rare — only about two and half metric tons of the rocks have been mined, usually from stream beds, since their discovery. Like white diamonds they are the hardest minerals on earth and can only be cut by other diamonds — it takes 6,000 pounds of pressure per square inch even to dent one, says Haggerty, who managed (barely) to accomplish that much in his laboratory after “seven days and seven nights” of effort. Carbonados were used in the Suez Canal’s construction to break up other rocks. Unlike white diamonds, carbonados are porous and agglutinated, meaning they’re comprised of clusters of crystals lurching every which way as opposed to the near uniformity of their clear counterparts. As a result they’ve got more cutting edges than other diamonds, and were used by the French in the 19th century to carve and sand hardwood for furniture. The largest carbonado ever found measures 3,167 carats, 60 times larger than the largest clear diamond. Found in Brazil where it was named Sergio, the crystal weighs 1.4 pounds.
The rocks are a puzzle: scientists know what carbonados are but have only taunting clues where they came from. Though they are as hard as white diamonds and, like those diamonds, formed when ordinary carbon was subjected to immense heat and pressure, carbonados appear to be significantly younger — about 3.2 versus 3.5 billion years. Their estimated period of origin is out of sync with the volcanic evidence. The riddle of the carbonado has long been the subject of debate, and explanations include a theory that carbonados were born as the result of heat from natural radiation, the impact of rocky asteroids or exploding stars. Still, says Haggerty, “no satisfactory explan- ation exists for their origins. They may reveal a new geological source for diamond forma- tion that hasn’t been recognized.”
Not long ago Haggerty fanned the flames of the carbonado debate when he put forth a thoroughly original hypothesis — the carbonados of Africa and South America come from the same meteorite or meteorites. Haggerty “stunned the experts,” the New York Times reported, with his theory that billions of years ago dis- tant exploding stars rich in carbon produced dense clumps of diamonds from the shock waves and pressure. Car-bonados, he speculates, could be the resulting diamond aggregates, black diamond boulders that entered our solar system and plummeted to earth, fragmenting in the process. The idea of diamonds in meteorites isn’t new; it was first discovered a decade ago that tiny diamonds can form that way. But after comparing values for carbon isotopes’ radioactive decay in various ancient rocks and meteorite samples, Haggerty began to suspect that carbonados come from a new class of “presolar” meteorites, long-surviving fragments of which, sucked into our solar system by the sun’s gravitational pull, eventually fell to earth through the oxygen-poor atmosphere of the pre-Cambrian period.
“When you put all the pieces together,” says Haggerty — the apparent presence of a certain type of weak chemical bond, the isotopic frequencies of long-decaying carbon isotopes, and the rocks’ signs of intense heating and shock — it seems as if these black diamonds formed 2.6 to 3.8 billions years ago. “Beginning about 4.5 billion years ago the earth was pummeled by meteorites, and this lasted for 5 million years,” he says. “We don’t see the scars they left because of erosion — the evidence was destroyed on earth — but it is beautifully preserved on Mars and the moon. That’s because those atmospheres are low in oxygen, which would turn the meteorite fragments into immense fireballs. But nearly 4 billion years ago the earth’s atmosphere had little or no oxygen, and so the black diamonds could have rained down unimpeded.” So why would carbonados be found only in Brazil and central Africa? It Haggerty’s right about the diamonds’ origin, they fell to earth before an ancient block of the earth’s crust fractured into South American and Africa. ‘“Look,” he says, gesturing to a world map over his desk. Immediately I see that the two continents fit together like a jigsaw puzzle.
Not everyone is convinced. Haggerty’s model has been criticized because of the carbonados’ small size — what made the fragments splinter to such an extent? — and because some isotopic data don’t jibe with Haggerty’s presolar profile of the rocks. Haggerty doesn’t mind the naysayers, who serve, in the true spirit of scientific inquiry, to fuel his enthusiasm. He is consumed by one goal “to produce a quantitative definition of a carbo-nado.” “It’s kind of an inverse fascination,” he says, noting the irony of these prosaic-looking rocks capturing his imagination after years spent in the hypnotic glare of perfect white diamonds. “I’ve been fixated by these objects for two years,” he says, turning a carbonado over in his hand. “They’re so nondescript, and yet they have this incredibly rich history.”
Soon after our meeting Haggerty was off to Pretoria, South Africa. It was to be his first visit since the days of apartheid, a policy of which Haggerty was deeply ashamed; here was a devil with whom he refused to dance. Returning to Nelson Mandela’s South Africa will be a happy homecoming for the ambitious boy from the high veldt who fell in love with diamonds, which brought out the very best in him.