Black Sands Of Montauk Go Beep! Beep!
On a January morning this year, Cliff Kalfaian grabbed his dog and his 15-year-old handheld Geiger counter, an instrument that resembles a calculator and measures ionizing radiation. He headed from his house in Montauk toward Oyster Pond on a leisurely stroll. Mr. Kalfaian studied geology in college and still, almost 30 years later, likes to sample rocks on his hikes. As per his other walks, he set out with no real expectations, but as he headed east, crossed the bend at Shagwong Point and neared Big Reed Pond, his Geiger began beeping like it had never before.
Mr. Kalfaian followed the intense clicking. Normally, he hears about 50 clicks a minute. The beeping continued to quicken and soon skyrocketed to 700 counts per minute. He grew excited at the prospect of finding radioactive minerals, which to him would be like uncovering buried treasure. Near the pond, he saw before him a black sand deposit, like a late-afternoon shadow cast across the tan shore. He picked up some of the radioactive grains and they weighed heavy in his hand. He guessed they might contain iron.
Giddy from his discovery, Mr. Kalfaian returned the next day equipped with a shovel, sample jars, and a magnet. He used the latter instrument to draw out the magnetic grains and separate them from the nonmagnetic ones, the ones that contained the radioactive minerals. When he was through, he saw the radioactive pieces, dark pinkish specks resembling a garnet stone, flecked with white grains.
Mr. Kalfaian found the radioactive sands in the area to be widespread and surmised it had occurred naturally, not from poisonous chemicals. But the big question loomed in his mind: Where was it coming from?
Back at home, he shook those remaining particles onto a slanted board until the white grains rolled away and only the black sand remained. His Geiger counter showed that the clicks had reached 800 per minute.
Mr. Kalfaian is not the first to discover the black sands of Long Island. In 1961, a man named Norman E. Taney determined the mineral content of the sands between Westhampton and East Hampton to range from 2 to 8 percent.
The sands at Montauk Point were especially mineral-heavy. A sample of magnetite, a naturally occurring iron oxide, tested at 25 per cent in a sample taken there.
Gilbert Hanson, a professor at Stony Brook University who studies the geology of Long Island, guessed the sand Mr. Kalfaian found was made of monazite, a rare-earth mineral laced with garnet, magnetite, and other dark minerals, all of which Mr. Kalfaian had surmised as well.
A 1963 report by Wallace de Laguna titled “Geology of Brookhaven National Laboratory and Vicinity, Suffolk County, New York” confirms Mr. Hanson’s theory for other parts of Long Island, not just Montauk. Scientists analyzed monazite samples from Baiting Hollow beach sand to reveal a little over 8 percent thorium oxide and the rest uranium. Another sand sample made of zircon, a gemstone, showed no trace of thorium, which is the ingredient that makes the sands radioactive.
“This confirmed the tentative conclusion reached from the counting measurements that the greater part of the local activity is due to the monazite,” the report states.
“It is not surprising or of concern. At least to me,” wrote Dr. Hanson in an email about the radioactive sands Mr. Kalfaian came across.
Dr. Hanson later explained, “It’s just a natural part of the sand, and when the wind, for example, blows across a sandy beach, it’ll tend to pick up the quartz, which is lower density than the black minerals.” These dark minerals are then left behind and sprinkled across on the beach.
The black sands here were mined for their iron content during colonial times, according to a report by Brookhaven Lab and Stony Brook. They have been discovered in Brazil, India, and other parts of the United States as well.
For some, like Mr. Kalfaian, the sands represent an earthen beauty and geology at work. Dr. Hanson, too, spoke affectionately about the sand, like a relic of history. He takes his students to study these minerals on field trips and said when walkers come across it, some like to bottle it up as a keepsake.
Dr. Hanson had one small reservation, though.
“I wouldn’t eat it,” he said. But then he laughed. “I wouldn’t eat any kind of sand.”