Robert Thorson, a geologist, was flying to give a speech at a Stone Foundation meeting in Oregon. As a geologist, he was carrying-on a rock specimen as a prop for his talk. Well, that was his plan, anyway -- before TSA gave him no alternative other than to throw the rock away:

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.

What a maddening world we live in. If it's not an affront to peaceful communication, it's succumbing to the idiocy of the TSA, which is nothing more than your typical governmental agency.

Below is a list, mostly off the top of my head, of items that would be allowed on a plane but could easily be used as "low-tech", "dual-use" weapons:

• High heel shoes
• Steel-toe boots
• Virtually any laptop
• Pens and pencils
• The metal rods used to roll luggage through the airport
• Crutches (Or a cane)
• A toothbrush

The following items, all of which are more dangerous than even a moderately sized rock, are explicitly allowed per TSA:

• A corkscrew
• Knitting and Crochet Needles
• Scissors (Blunt), Blades (less than 4 inches)
• Umbrellas
• Tools (Seven inches or less in length - including screwdrivers)

And I'm sure I missed a few. Do you hear the twilight zone music? (H/T boingboing.net)