Historian of currency

Cupped in Ronald Cristal's palm is a tangerine-sized orb of the kind that artillerymen of the American Civil War might have used for their breech-loading cannons. It dates from that era, too, so you might think it a nice, antique paperweight.

Tell Cristal that and he will gasp at your ignorance. What the American-born Thai numismatist is holding is not artillery ammunition at all. It is a "bullet coin" issued by the Siamese king Rama IV.

Engraved with the king's own seal of a tapering Siamese crown, the bullet coin (the largest item of indigenous weight-based currency) was denominated as 80 baht. That may not sound like much these days — just over $2 — but back in the mid-19th century, it was worth a fortune. It still is.

Cristal bought the coin at a Bangkok auction for more than 30,000 times its denominational mark, 2.5 million baht ($80,000), to be precise. He could sell it for several times that amount to foreign collectors, he says, but he won't.

Obsessive, Cristal certainly is, but yet he belies the stereotype of coin collectors as reclusive oddballs hunched over their treasures with monocles or a watchmaker's eyepiece, brows furrowed in scrutiny.

Despite spearheading a well-established law firm in Bangkok, Cristal seems to spend most of his time on the internet comparing notes with fellow collectors worldwide — retired postal workers, computer programmers, high-flying executives and everyone in between.

Search for exclusivity

Whatever one may have thought, it turns out that serious coin collecting isn't just a namby-pamby pastime; it is a spirited undertaking fuelled by competitive zeal. Or, as Cristal puts it: "It's about owning something no one else in the world has." And he does. Lots of it.

If you showed up at your local grocery store with a human head or two in exchange for necessities, you would hardly be welcome. Not so among ancient headhunters on the Indonesian island of Sumatra, for whom the trophies were valuable mediums of exchange.

Such monetary relics, Cristal concedes, would be extreme even by the flamboyant standards of his own collection. Yet, for the most part, if ancient Thais, Laotians or Burmese ever used it, Cristal wants it, too.

"Have a look at these!" he invites, pulling golf-ball-sized curios from one of his two top-of-the-line, drill- and fire-proof safes, in which lie the 2,000-plus prized items of his coin collection, minutely catalogued and arrayed meticulously in plastic trays.

Among them are items of "a pre-modern metallic monetary system" that worked alongside cowrie shells as more or less standardised tender. They date back 700 years to the Lan Na Kingdom in what is now northern Thailand.

"They may look crude," Cristal says, "but no counterfeiter can exactly duplicate them." He should know: He also collects modern and contemporary counterfeits.

Even within the world of numismatics, Cristal's specialty — South East Asian "curious money" — counts as wildly exotic fare. True, the Aztecs paid in cocoa beans, and gaudy parrot feathers once fetched quite a bit among certain tribes in Africa and Oceania. But genitalia-shaped currency? Or how about "bracelet money", which obviated the need for banks by making wrists into portable safety depositories?

Yet this numismatist's paradise, the American Numismatic Society notes, has been "almost entirely ignored by scholars and collectors".

Cristal agrees. "Most coin people," he laments, "only look at flat round coins with regular shapes and stamps [imprints]."

To remedy that situation, he is finishing a reference book on Thailand's pre-modern coinage, a Yellow Pages-size magnum opus with colour plates listing over 900 unique specimens (most from his own collection). The book is in draft form but Kusik Manodham, chairman of the Numismatic Association of Thailand, is heaping praise on it.

Unique magnum opus

The book follows such earlier tomes by Cristal as The Centenary Of Thai Banknotes and The Coins And Medals Of The Rattanakosin Era.

Cristal first set foot in Thailand (now his adoptive home) in 1971 during the Vietnam War. A military judge advocate, he was handling local settlement claims filed against the US Army. Then, one day, he wandered into a small shop peddling Chinese sycee (silver ingots), and, next thing he knew, he had bought the entire collection. Ever since, Cristal has been a constant presence at Bangkok auctions and flea markets, squinting at the wares of amulet merchants and old-coin sellers.

Unlocking another chest of his treasures, Cristal produces flat, elongated silver objects with the pimply texture of toad skin. No, they are not from the bag of a witchdoctor. Behold: "tiger-tongue money".

At least that is what romantically inclined collectors label this ancient Laotian currency, which locals called lat. The technology for replicating the old coins has been lost, but folklore attributes their spotty surface to the death throes of fire ants thrown into molten silver.

That is why, for people like Cristal, numismatics is more than an idle hobby. Trends and changes in primitive monetary systems, when decoded, can chronicle the trajectories of preliterate cultures and explain the cultural underpinnings of modern societies. "For one interested in the evolution of history," he explains, "it's interesting to see coinage as [tokens in the phases of] a historical evolution."

Cristal took Thai citizenship a few years ago. At his citizenship test, Cristal says, he whipped out the photograph he carries in his wallet of himself with the country's revered king, Bhumibol Adulyadej, who has a keen interest in old Siamese coins; Cristal boasts that he was granted citizenship without further ado.

But the numismatist cherishes his rapport with King Bhumibol for other reasons, too. "It's been a privilege," he notes, "to meet the man whose face is on every [present] note and coin."