By Dr. Robert Thorson

When is a rock not a rock? When you pass through airport security. Then it becomes a potential weapon, one capable of bringing an airplane down.

I’m mad. I can think of a better way to combat terrorism than taking mineral specimens away from geologists traveling to their conferences. I suggest we get U.S. forces out of Iraq, where our blundering entry and lingering occupation are inflaming anti- American sentiment throughout the world.

There are two versions of what happened to my specimen at Bradley International Airport, Hartford. In the first version, I was completely at fault. Out of ignorance, I broke some unwritten rule. Then, in the name of homeland security, the Transportation Security Administration took my rock away.

In the second version, the federal government is at fault for not listing mineral specimens as prohibited items and for creating a climate so fearful of terrorism that it’s compromising our economic efficiency, personal freedom and instinct to trust one another.

I was traveling to Hood River, Ore., to attend the annual meeting of the Stone Foundation, an international organization of architects, sculptors, stonemasons, geologists, engravers and engineers united by their love of stone.

To enhance my speech, I nestled one of my favorite specimens between my underwear and shirts in a carry-on bag because I never check luggage on business trips. My banded chunk of the Hebron Gneiss (pronounced “nice”) resembled a broken slice of layer cake composed of licorice and cream cheese.

In retrospect, I suppose I could have put the grapefruit-sized specimen inside my sock, swung it around my head like a mace, charged the cabin and attempted to hijack the flight. This, of course, never occurred to me until the zealous inspector declared my rock a “dual-use” item.

“What, pray tell, is a dual-use item?” I asked. I’m afraid I chucked just a little, causing her to glare, withhold a satisfactory answer and call her supervisor. He hefted my rock, scrutinized it for a moment, and agreed that my specimen was indeed a dual-use item, meaning a potential low-tech weapon. During those uneasy moments when I thought I would be detained, I wondered if a doctor’s stethoscope would also be declared a dual-use item, since it could be used to strangle a pilot.

The inspectors did give me the option of returning to the ticket counter to check my specimen as baggage. However, having waited more than half an hour for my security clearance, I decided that I didn’t have enough time. “Can I claim the rock when I return?” I asked. Their answer, a resounding “no,” forced me to choose between possibly missing my flight, and abandoning my rock forever.

I capitulated, surrendering it to that great unmarked graveyard where confiscated items will spend eternity. If rocks had feelings, my beautiful specimen would have been crying as it was hauled away.

My gneiss was not without sentimental value. It has been my traveling companion for three years, and a touchstone for thousands of people who have attended my talks. And though my rock is gone for good, what worries me is that some analyst — perplexed by the usual nature of my dual-use object — will write a report to be sent up the bureaucratic food chain.

Who knows? Perhaps your tax dollars will be used by an internal think tank of agency hire-ups to ponder why on earth a geologist would travel with a rock. Who knows? Perhaps the government will wiretap my phone or check my library records to see whether I have checked out a Koran or a book about stone-age warfare.

I’m a middle-aged, balding, blond and blue-eyed Scandinavian- American. If the gauntlet of untrusting looks at airport security intimidates me, then how much worse would it be for an Arab American? Would the threshold weight for rock confiscation be lower?

After my conference, I brought back a specimen of rhyolitic ignimbrite (welded volcanic ash) to mitigate the loss of my nice gneiss. This time, I took no chances. I put it in my carry-on bag and checked it as luggage to ensure that my new rock would make it home, which it did.

What’s next for airport screening? My dual-use laptop?