Karin Cartwright's favorite crystal is a deep purple, Brazilian amethyst geode. She calls it her "life insurance policy."

Three years ago, while hospitalized at the National Institutes of Health for treatment of cancer, Cartwright surrounded herself with hundreds of quartz crystals. Her doctors scoffed at the zaniness but allowed her to keep the crystals so long as she kept up the conventional treatments they prescribed.

No argument from Cartwright. At 42, with her life on the line, she wasn't about to jilt science for parascience. But she figured both together improved her chances. Soon, the nurses were asking if they could bring in other patients to see her crystals. Cartwright gave each of them a small quartz to take back to their own room.

"For me, the healing had started," recalls Cartwright, who lives in Arlington. "Those crystals eased my own depression and my own dilemma. They lifted a great weight off me."

Cartwright has no doubts today that the crystals were critical to her survival. "Crystals seem to bring a particular joy and healing aspect to people," she says. "I've been accused of saying crystals heal. I've never said that. Anything in your environment that attunes you to your higher self is a healing tool."

Yet, in a year that has seen crystals replace spiritual channeling as the newest New Age rage, Cartwright admits she believes in many claims of crystal power. So, it seems, do a growing number of other Americans.

Proponents proclaim crystals a tool of the so-called "New Age" -- a term that is becoming a catchall for a wide range of inner development disciplines and beliefs.. Skeptics say crystals are part of an occult assault on the American mentality that, according to the University of Chicago's National Opinion Research Council poll reported earlier this year in American Health magazine, has two-thirds of American adults admitting they've had psychic experiences.

Both sides mention Shirley MacLaine. Ever since the actress-cum-spiritualist revealed her personal contact with extraterrestrials and spiritually channeled wisdom, via a book and TV mini-series last year, the New Age has come out of the closet -- and so have crystal gazers.

One of the top suppliers of wholesale crystals and crystal jewelry reports from California that it is swamped with orders from more than 400 dealers nationwide. Prices have jumped with the orders; stones that five years ago cost 50 cents now are priced at more than $5, says one dealer.

Mainstreaming the New Age also has inundated the publishing industry's upcoming book releases. In the next three months, more than a dozen titles on crystal power alone will be released, not to mention numerous other books on life after death, Eastern religion, the occult, dreams, among others. One sales gimmick adopted by at least five publishers packages a sampling of crystals with each book. The new release Crystal Oracle supplies "five crystals and a velvet casting cloth to be used for interactive forecasting."

Bantam Books executive editor Toni Burbank says MacLaine "suddenly made it respectable ... to deal with reincarnation, out-of-body experiences, spiritual messages, channeling, and so on."

Last month, Karin Cartwright reopened her shop called The Crystal Center following an aborted stint last year. Located in the Yes! Natural Gourmet building in Georgetown, it displays thousands of crystals -- from $5 quartz points to expensive amethyst clusters. The faint incense is as mellow as the background music -- New Age chords and reverberations sometimes called "ear candy," with titles such as "Inside The Great Pyramid" or "Life on the Double Planet." Cartwright calls crystals "God's toys." At any one time, she may carry around as many as 100 crystals or only one. She is looking to move the shop soon to the Blue Ridge Mountains near Charlottesville -- where the crystals have directed her.

About two years ago, Paul Caruso's migraine headaches had become debilitating. He had spent $1,600 on doctors bills and taken knock-out pills, all to no avail. At 33, Caruso knew the headaches that hammered his brain five times a day, up to six days a week, threatened his job as branch manager at a Perpetual Savings Bank in the District.

Then, while vacationing in San Francisco, Caruso bought an amethyst at a Haight-Ashbury crystal shop. He began reading about crystal healing. Day after day, Caruso would sit in a chair, grip the amethyst in his left hand, breathe deeply and meditate on the healing nature of the crystal. In four weeks, he says, his headaches stopped. He hasn't had one in eight months now. "I'm not saying people shouldn't go to a medical doctor or pursue certain logical steps when dealing with illness," says Caruso, who lives in the District. "But I feel crystals are good healing tools."

A year ago, Caruso grew distressed over the "astronomical increase" in the price of crystals. He says that's why he got into the business. On weekends, he sells stones at the Farm Women's Cooperative in Bethesda. He also conducts his Crystals Way workshops on choosing, cleansing and charging crystals. "If somebody isn't into any of the metaphysical properties of crystals, that's okay," says Caruso. "The crystal's energy is going to help them anyway, whether they believe in it or not."

Dr. Richard Gerber is an internist in Warren, Mich. A researcher of alternative medical treatments, recently he has been experimenting on family and friends using quartz crystals. "Mainly for local pain relief, headaches, menstrual cramps," says Gerber. He also says it works.

Gerber believes the ability of crystals to relieve those aches has a scientific basis -- but not one that has yet been recognized in conventional physics. "Some of this is a little far out," he says. "And some people have gotten overzealous. They've got crystals doing everything from cooking dinner to vacuuming their houses ... But energy medicine is an area you're going to hear a lot more about in the next 15 years."

Dael Walker doesn't qualify the unusual claims he makes about crystals. It's been almost 13 years since Walker, then a successful building contractor in northern California, lay sleepless on his bed the night of his 40th birthday. He says he was "just a plain old Joe" -- no metaphysical wizard, no guru or weirdo -- who wanted more out of life.

He was attracted to a crystal at a psychic fair a few days later, so he went out and bought one -- a 4-inch long quartz, cloudy but with a clear point. "I noticed I wanted to keep it in my hand all the time," recalls Walker, who today owns a store and workshop called The Crystal Co., in Pacheco, Calif. "A lot of intuitive things started stacking up, too. I knew what somebody was going to say before they said it; I knew when the phone was going to ring before it rang."

To his amazement, says Walker, when he hurt himself jogging, he'd place his crystal over the injury and the pain disappeared in minutes. Walker says his practical experimenting lead him to write The Crystal Book -- an $8.95 hands-on guide he published himself that instructs in the amazing power of the stones. "Now all of that stuff is suspect," he admits, "unless you can show it works."

Walker insists it does work. He says he has heard testimonials from people all over the world, from as far as Katmandu, who have changed the taste of their drinking water through crystal charging, who contact spiritual guardians via crystals, who have healed the sick with crystals.

These are the kinds of claims that infuriate some scientists. The problem that phenomena such as crystal power poses for modern science is that all of the evidence is anecdotal. Believers make claims, but scientists say they are unable to reproduce those metaphysical happenings in a controlled laboratory setting. Hence, the traditional standoff: science versus faith.

But the crystal craze, scientists contend, may be even harder to debunk than, say, UFOs. That's because science itself has recently discovered rather extraordinary properties and uses for crystals. Believers seldom fail to point out that 20 years ago the crystal lasers now used for delicate eye surgery were the pulp of science fiction.

William Tiller, a professor of material science and engineering at Stanford University, believes that "in the long run" science will make important discoveries about crystals and subtle energies. But he says unfounded claims of the near miraculous only sidetrack that work. "I have not seen any data that I think is reliable, accurate and self-evident, that says that effect is operating," says Tiller. "It is important that we provide a good experimental base for this kind of thing and that people not make great claims without real evidence."

Lawrence Jerome is the author of the 1975 book Astrology Disproved and founding member of the Committee for the Scientific Investigation of Claims of the Paranormal, a national group that last year exposed fake faith healers. "Certainly crystals are very beautiful and intriguing," says Jerome, "but the idea that they can channel energy is a bit absurd.

"If you want to use the crystal as something to focus on, there's nothing particularly wrong with that. Of course, people selling the crystals are making a goodly amount of money."

Uma and Ramana Das Silbey may be the crystal success story of the decade -- certainly in monetary terms. Five years ago they started a little business from their kitchen table in San Rafael, Calif., a typical Mom and Pop cottage industry trying to wholesale crystals and crystal jewelry that Uma designed herself.

According to Ramana Das, sales volume doubled each year since, and this year should break $1.5 million. He says Uma Silbey Inc. is the IBM of crystaldom, supporting a staff of 40 employes. "One reason our stuff is so much in demand and so nice," says Ramana, whose sales rap is more Madison Avenue than meditative, "is because we acknowledge and use the energies of the crystals as well as bringing out their sparkling beauty and qualities of nature."

The book hasn't hurt either. The self-published Complete Crystal Guidebook sold about 70,000 copies in 10 months, mostly through mail order and word of mouth. Bantam Books was so impressed that it reprinted the guide this month for $9.95.

The Silbeys contend crystals are much more than the metaphysical pet rock of the '80s. "This is a 21st century phenomenon and we're at the beginning of it," Ramana Das says. "The techniques are like Model T Fords. They work. They're crude. But when we get into the 21st century, crystals will become a commonplace part of everyday life."

In Danville, Calif., just east of San Francisco, Gloria Dodd fits sick dogs and cats into halters studded with quartz crystals. "I've had a lot of success with crystals," says the doctor of veterinary medicine. She claims that crystal technique with acupuncture has reversed the symptoms of animal arthritis, crippling hip disorders in dogs and feline leukemia.

"With no other treatment than just putting this halter on a painful and crippled animal," she says, "within a few days or weeks ... they are acting like a normal dog."

But recently Dodd has redesigned the original healing halter. She has substituted for the two double pyramids of small quartz crystals that were stitched into the garment a simple sewn-in design representing crystals -- with comparable results. She says she did it out of concern that the current crystal craze will ravage the world's supply of stones.

"The world is going crazy over crystals ... ," she says. "And we are mining the hell out of quartz crystals in the Earth's crust that maintain the electromagnetic field of the planet. Now what happens when you remove all these quartz crystals from the Earth's surface? I'm very worried about this."