IN LATE 1955, Robert Wentorf Jr. did something close to alchemy. He bought a jar of peanut butter at a local food co-op, brought it into his lab and then turned a glob of the stuff into a few tiny diamonds.

Wentorf and his three coworkers at General Electric Research and Development Center in Schenectady, N.Y. also transformed roofing pitch, coal, wood and other carbon-containing materials into diamond grains as fine as flour and as big as sesame seeds. These spectacular experiments showed that almost anything with enough carbon atoms in it could double as a diamond in the rough. Wentorf recalls receiving anxious letters from prospectors who envisioned the value of their natural-diamond investments deflating into peanuts.

Diamond, the hardest substance known, is made up of carbon atoms arrayed in a crystalline lattice {see illustration}. Researchers first synthesized it by recreating the high temperatures and gargantuan pressures that produce diamond deep in the earth. Since its commercialization by GE, this rugged and expensive high-pressure process has become the basis of a half-billion-dollar-a-year industry whose end-products include diamond-coated tools for drilling, mining and quarrying, for precisely machining automotive parts and for producing dies used by wire-makers.

Yet even before the high-pressure technique became popular, some researchers had their eyes on a completely different way to grow diamonds using a cheaper, low-pressure process called chemical vapor deposition (CVD). In that method, carbon-containing gases such as methane (CH ) decompose under intense heat within a chamber kept at or below normal atmospheric levels. The freed carbon atoms collect and assemble themselves into diamond on the surfaces of materials placed in the vacuum chamber but held at lower temperatures. This system had been used experimentally since the '40s, but at diamond growth rates so extremely slow as to be commercially useless. By the mid-'80s, however, a series of Japanese innovations on American and Soviet CVD techniques made the technology feasible and provoked a worldwide boom in further research.

The CVD approach is not only far less costly than the high-pressure method, but offers the prospect of coating far more materials with a substance that holds more world records than any other in the materials game. As a result, the synthetic diamond industry glitters with refound promise of new, far-ranging technological possibilities and far bigger business.

Researchers have even turned the carbon in bourbon and sake into diamond films using low pressure techniques, though methane (aka swamp gas) remains the source of choice.

Now "you can coat virtually any material with diamond," says materials scientist and diamond-maker Rustum Roy of Pennsylvania State University. That means engineers can add diamond's scratch-resistance, ability to draw away heat and other superlative properties to materials that lack these traits.

"Diamonds are going to be everywhere," predicts John Angus, a chemical engineer at Case Western Reserve University who has been a leader in the field since the 1960s. "They'll be in pots and pans, on drill bits and razor blades, in Xerox machines and on hard disks." {See box.} Beyond the Big Squeeze The first commercially promising account of synthetic diamond hit the presses in July 1955, when Wentorf and his colleagues published an historic paper in Nature. They described a process for turning graphite -- the sooty, all-carbon stuff in pencils -- into its mineralogical cousin diamond. The feat so impressed government officials that they imposed a gag order on the project for awhile.

The process requires hell-on-earth conditions: temperatures of 2500 F and pressures equivalent to more than 50,000 atmospheres, or about 1 million pounds per square inch. That's an environment the GE scientists knew would be comfortable for diamond and intolerable for graphite. The squeeze of the presses was so severe that the team had to design especially rugged vessels that could withstand the stress.

At normal temperatures and pressures, carbon prefers to take on the structure of graphite: hexagonally-arranged carbon atoms that form into stacked layers each of which resembles a sheet of molecular-scale chicken wire. But graphite just can't hold together under the extreme conditions of the high-pressure process. In the presence of a metal catalyst and a tiny seed diamond held at sub-melting temperatures, graphite's carbon atoms disengage from each other, migrate through the now-melted metal to the seed and reconfigure themselves into a sparkling new arrangement. Instead of the chicken-wire configuration, they form into strong covalent bonds in a super-uniform tetrahedral pattern.

"These weren't what you ordinarily think of as diamonds," Wentorf notes. Impurities and crystal defects made them dark and opaque like black sand. The peanut-butter diamond grains had a greenish tinge due to nitrogen atoms formerly locked within protein molecules. GE subsequently refined the process and can make beautiful clear diamond grains that range in size from microns to millimeters. In 1970 they even found a way to make large gem-quality diamonds. These, however, proved too expensive for the jewelry market, and still are.

But CVD's prospects are brighter than ever. "Recent success in deposition of diamond and diamond-like coatings on a variety of substrates at practical growth rates is one of the most important technological developments in the past decade," concludes a technology-assessment report released in June by the National Research Council here. "Indeed the ultimate economic impact of this technology may well outstrip that of high-temperature superconductors."

The world's yearly synthetic diamond production, predominantly by companies in the United States, South Africa, Japan and the Soviet Union, totals over 300 million carats. At a fifth of a gram per carat, that amounts to more than 60 tons of abrasive diamond grit valued at $500 million. (Natural rough-diamond production weighs in at about 19 tons per year.) By contrast, market researchers at Gorham Advanced Materials Institute in Maine expect a low-pressure synthetic diamond industry to haul in $1 billion by century's end; a Japanese firm multiples this estimate sixteen-fold.

These predictions rest on the growing finesse and reliability with which researchers can deposit films of diamond and "diamond-like" materials onto surfaces as diverse as paper and silicon. Since diamond is the hardest material known, transparent diamond coatings would perpetually protect eyeglasses, wristwatch crystals and other surfaces from damage. Coating a computer's hard disk platters would protect them from "crash" damage by the read-write heads that fly above the platters at 3,600 rpm.

Because it absorbs almost no light, diamond offers ideal protection for optical fibers and space-based radiation sensors. In fact, less perfect diamond-like coatings might be preferable since they form a smooth layer rather than a multifaceted light-scattering sheet. For the same reason, engineers are eyeing diamond-like coats as lifelong lubrication for things like ball bearings.

Diamond carries heat away at unexcelled rates, almost never reacts with anything -- and then only at high temperatures -- and is an excellent electrical insulator. So diamond coatings and heat sinks could enable engineers to make faster electronic chips that operate well at high temperatures. Some scientists even envision diamond semiconductors that might place electronic technology in hot jet engines, radiation-ridden reactors or other hostile environments that disable silicon-based chips.

"Diamond would be the best semiconductor if you could make it work," notes Roy. By growing synthetic diamond in the presence of boron, several laboratories already have made crystals that behave like semiconductors. These crystals still contain too many defects and cannot yet be reliably integrated with other electronic components. A Hard, Gem-Like Flame The detailed physical and chemical mechanisms underlying the CVD process remain mysterious. But that hasn't discouraged researchers from discovering reliable conditions the hard way: trial and error, eased by an admixture of intuition and theory.

"You really only have to know a few concepts about how crystals are put together and then make some intuitive guesses," says Robert DeVries, a retired GE veteran of diamond research who worked on the NRC report. "Most of these advances are not made by theoreticians, they're made by intuitive materials scientists playing around in a sand box."

For CVD diamond-makers, that "sand" takes the form of carbon-containing gases. A vacuum chamber serves as the "box." The chamber houses a localized source of intense heat -- a tungsten filament or a microwave-generated plasma (ionized gas), for example. The heat decomposes a carbon source, usually a small amount of methane carried in a steady flow of hydrogen gas. Carbon fragments from the methane are deposited as diamond film on target surfaces which are also in the chamber but kept in the 600 to 900 C range. The hydrogen gas apparently hinders the formation of graphite while promoting diamond growth.

By regulating the hydrogen-hydrocarbon ratio, the pressure inside the chamber and the temperature of the target materials, researchers have succeeded in growing diamond films at rates as fast as 100 microns (millionths of a meter) per hour onto relatively large and intricate target areas. Thousands of tiny diamonds nucleate on the deposition surface and then grow together into a continuous polycrystalline film.

Researchers now routinely produce crystalline diamond films or diamond-like coatings. The latter lack true diamond's broad-scale crystalline order, either because they contain lattice-disrupting hydrogen atoms or because their carbon atoms bond in more random ways. Though less perfect than true-diamond films, diamond-like coatings form on substrates approaching room temperature and make smoother surfaces.

The first CVD diamond products already have hit the market. Deep-pocketed audiophiles can buy tweeters with diamond-like diaphragms made by Sumitomo for Sony. Seiko plans to market watches with scratch-proof diamond-coated crystals. Crytallume in Menlo Park sells diamond-coated windows for infra-red scanning systems important in analytical instruments and missile guidance. IBM scientists use a CVD process to fashion light-filtering diamond patterns on chip-making masks, which they hope to use in making smaller electronic components. In July, GE announced that it was combining CVD diamond synthesis with its high-pressure technique to make diamond that exceeds natural diamond's ability to dissipate heat and withstand laser damage.

The seemingly alchemical dream of turning baser materials such as peanut butter and whiskey into precious gems has been realized over and over again. Two years ago, a Japanese researcher even reported depositing diamond films onto cooled metal surfaces held in the flame of a low-cost oxyacetylene torch such as those used by welders. That work has been repeated by James Butler and his colleagues at the Naval Research Laboratory here. He's betting that the oxyacetylene route will become a big player in the coming era of CVD diamonds.

Whatever the exact CVD technique, materials scientists generally agree that low-pressure diamond-film technology is poised to become a major industry.

But swelling to larger industrial scales won't be easy, especially for the U.S. research community, the NRC report concludes. The report recommends that theoreticians, chemists, optical scientists, electrical engineers and materials scientists all pool their talents for getting small-scale laboratory technology up to industrial speeds. To help, the report calls for expanded funding to "turn this emerging technology into a national pivotal technology."

Since such a scale-up requires the production of films with predictable and reproducible material properties, the report also recommends a coordinated effort to understand fundamental physical and chemical mechanisms underlying both diamond and diamond-like film growth.

For early diamond-makers such as Wentorf and Angus, the resurgence of interest in synthetic diamond research is a pat on the back. "But luckily no one has ever asked us to make peanuts out of diamond," Wentorf quips. "That would be much more difficult." And bad business, no doubt.

The Gleam Machine

SYNTHETIC diamond makers see no long-term obstacles to making diamond-based electronic components that run at higher frequencies, with more power and at higher temperatures than conventional devices. In satellites, for example, that would mean longer-running transmitters. Also, bulky cooling systems that now drain potentially damaging heat from electronic components would not be necessary with diamond transistors, which can operate reliably at much higher temperatures. This could shrink satellites to half their present size with a concomitant reduction in weight and cost. By dissipating heat 10 times more efficiently than silicon devices, diamond heat sinks can boost the performance of conventional electronics by enabling chip makers to jam more components on chips without worrying about overheating. That could lead to faster supercomputers.

Diamond might be useful on almost any optical surface, including windshields and house windows. Its transparency to nearly all wavelengths of light as well as its scratch-resistance make it suitable for coating otherwise fragile and vulnerable specialty windows and lenses, which serve in sensors and analytical equipment that scan infrared, optical, ultraviolet and even X-ray wavelengths. Diamond's high thermal conductivity and strength would enable engineers to build thin, lightweight mirrors important for harnessing high-power lasers either for industrial machining or military purposes. And coating optical fibers with diamond would protect the fine light pipes from abrasion, chemical degradation and moisture.

Mechanical engineers also have their eyes on diamond. A fine diamond coat on bearings, gears, shafts and other parts susceptible to wear would enable lots of machinery to run longer with less maintenance while maintaining precise tolerances. Surgeons already use blades made from natural diamond crystals, which cut tissue with a minimium of pressure. Diamond's water-repelling surface also keeps tissue from sticking and dragging. CVD techniques could make such blades commonplace. Diamond's durability, chemical inertness and resistance to bacterial and viral attachment make it a promising candidate for coating medical inserts such as artificial joints.

Ivan Amato covers chemistry and materials science for the weekly magazine Science News, from which this article is adapted.