mystery rock

Rocks similar to this one appear on Jekyll beaches. There is some amount of debate as to what they are. Some experts suspect they may be connected to prior industrial production.

At first glance, they appear like footlong or shorter bits of driftwood that have been rolling around in the sea for so long they turned black. But upon closer inspection, they are heavier than wood and give the impression of a stone of some type. But what are these rocks dotting the beaches of Jekyll Island?

It is up for some amount of debate. The Jekyll Island Authority’s director of historic resources, Bruce Piatek, and the JIA director of conservation, Ben Carswell, have had a friendly discussion for a while as to what the things are, but like many good discussions, this one has yet to reach a mutual resolution.

“Ben’s idea is that they may be of volcanic origin, my idea is that they’re slag from furnaced and industrial activities and coal,” Piatek said.

He went on to explain, “Normally what this stuff is, is the residue that’s left — so, if you’ve ever burned coal, you get the stuff that’s called clinkers, what’s referred to as clinkers, and it’s basically all the stuff that won’t burn. Because of the heat, it kind of fuses itself together and has a lot of air pockets in it, so it’s kind of this lightweight but still hard material. And it’s just kind of the refuse that gets shoveled out of … well, furnaces and such, that were used to power boilers and other such industrial activities.”

Piatek said he thinks the reason the rocks wash around in the water and get deposited on the beach is because they were used as fill to stabilize shorelines and other similar projects.

“I think that probably, earlier, furnaces where somebody just literally when the furnace got full, they’d send Joe over there with a shovel and tell him to dig this stuff out — dig it out and pile it up somewhere, and they would put it wherever they thought it should go,” Piatek said.

Carswell believes the stones come from the Caribbean.

“So, there’s active volcanism in the Caribbean … there’s an island in the Caribbean that’s had an active volcano going,” Carswell said. “Part of the island has actually been closed off and evacuated for years. So, active volcanism, ocean currents, trade winds tend to blow from east to west, and then you’ve got the gulf stream that comes up the coast, and comes relatively close to the coast of Jekyll, and so it’s not too hard for me to imagine, between winds and currents, things ending up washed ashore here.”

The volcano and island Carswell referenced is the Soufriere Hills volcano in Montserrat that began erupting in July 1995. According to the Caribbean Disaster Emergency Management Agency, within two years the volcano made most of the island uninhabitable and half the island’s population had to permanently evacuate.

The CDEMA states the Soufriere Hills volcano is the only one in the Caribbean currently erupting, though the Kick ‘em Jenny undersea volcano — located about five miles north of Grenada — has erupted at least 11 times since 1939, making its eruptions the most in the region during the last 100 years.

More from this section

Efforts to make the new $3 million-plus MOSAiC museum on Jekyll Island become reality are on track as Jekyll Island Authority staff and contractors work within historical specifications, JIA Historical Resources Director Bruce Piatek said Tuesday.