The young miners here are known as wanapollo, Swahili for spacemen. Several times a day, they emerge from half a mile below the earth, their dark bodies coated in glittering graphite dust.
They are in search of tanzanite, a gem found in a 5-square-mile patch of scrub near the base of Mount Kilimanjaro.
A few months ago, Mohammed Abubakar supported his mother and eight siblings with money earned from mining the blue-violet stone. But since Sept. 11, reports that Osama bin Laden's al-Qaida network controlled a chunk of the tanzanite trade have sent the price of the gemstone plunging by about 70 percent, slashing his earnings.
U.S. retailers Tiffany & Co. and Zale Corp. and the QVC television shopping channel, which together sold about 80 percent of the tanzanite, have suspended sales, saying they didn't want to be associated with bin Laden _ if allegations regarding his links to the stone are true.
In recent years, tanzanite has become one of the most popular colored gemstones in the United States, thanks to jewelers who tout it as less expensive and bluer than sapphire.
"Soon, these stones are going to be as valuable as concrete," Abubakar grumbled to a reporter recently.
Abubakar's economic pain demonstrates how the U.S. war on terrorism is being felt across the globe _ from travelers at international airports to poor miners in Tanzania's hinterlands.
Mererani has become a town filled with recrimination and questions: Did an influential Muslim cleric urge believers to sell stones to people allegedly linked to bin Laden? What role, if any, did a wealthy tanzanite dealer play in helping to fund al-Qaida? And most important, can tanzanite survive the taint of bin Laden?
Tanzanite's links to bin Laden were suspected long before Sept. 11, but no one seemed to care. During last year's trial of four men accused of the 1998 bombings of the U.S. embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, a prosecution witness testified that al-Qaida operatives fattened the terror network's coffers by trading in commodities including animal hides, sugar and tanzanite.
Federal prosecutors alleged that Tanzanite was the code name for bin Laden's personal secretary, Wadih El-Hage, who was convicted by a New York federal jury for his role in running bin Laden's businesses during the mid 1990s.
From Nairobi, El-Hage operated a company known as Tanzanite King. El Hage's diary, which FBI agents seized in 1997, detailed how he traveled to London, Los Angeles and San Francisco, marketing the gem to jewelry stores, according to federal sources.
Another key player, according to miners, brokers and industry officials, was Sheikh Omar Suleyman. They said that as head of the Taqwa mosque in Mererani he urged believers to sell their tanzanite to bin Laden loyalists, who smuggled the gemstones to Dubai, United Arab Emirates. Suleyman denied the allegation.
Tanzanian authorities worry that reports about bin Laden's involvement with tanzanite could destroy the livelihood of tens of thousands of mining families.
As the U.S. market for tanzanite is drying up, Mererani, which once resembled a California gold rush town, is slowly becoming a ghost town. Bars have gone quiet. Many people who came here dreaming of expensive cars and luxurious homes are returning to their villages empty-handed.
"It's all because of this bin Laden," Abubakar said. "That man should be caught and killed straight away."
Tanzanian officials say they would need to conduct an exhaustive investigation to determine al-Qaida's interest in the gem.
Abubakar and other miners say they long for the period before Sept. 11, when all that people in Mererani cared about was making money, providing for their families, and having a good time.
Tanzanite transformed Mererani into a major job center. An estimated 30,000 people from across Tanzania relocated here. As more of the brown ore _ it turns blue after being heated _ was brought to the surface, mud huts were replaced by brick houses sporting satellite dishes. Toyota Land Cruiser taxis ferried workers from Kilimanjaro International Airport to the mines. Bars and brothels with "New York" and "Hollywood" in their names appeared overnight.
Abubakar heard about it in his small village outside Arusha, about 80 miles away. He made the two-hour trip and worked out a deal with a mine owner: He would toil for food, a place to sleep in the shacks on the mine premises and a small commission.
To blast a mining tunnel, Abubakar and co-workers, some of whom look no older than 13, stick dynamite in an air pocket, then scamper up a ladder cobbled together from scrap lumber to escape the blast.
The air in the mine after the blast can top 120 degrees and can be lethal. The miners have little or no safety equipment _ no goggles, no masks, not even headlamps, although cheap flashlights are strapped to their bare heads or, sometimes, helmets with strips of black inner-tube rubber.
The miners must climb ladders with plastic sacks containing rubble from the bottom of the mines. Occasionally, an exhausted miner drops his 50-pound sack on comrades below.
Before Sept. 11, Abubakar earned up to $100 a month. That was enough to support his entire family and to pay for his numerous sprees at the brothels.
For Mererani, the biggest blow came when Tiffany, the gem's main retailer, stopped selling tanzanite at its 126 stores worldwide. The company, said spokeswoman Linda Buckley, bought tanzanite from established U.S. sources but "it's very difficult to track the origin of a stone as it travels from rough to cut and polished."
Tiffany "has no reason to believe that the tanzanite we purchased in any way benefited the al-Qaida network," she said. "But we felt that until we have more information, it's best to suspend sales."
Suleyman, the head of the local mosque, denied in an interview that the mosque was used in bin Laden's tanzanite trade.
"The Koran teaches that we can't use the mosque for these purposes," he said. "It would be a big sin to do so."