But later that day, on the rim of Halemaʻumaʻu Crater, some 360 feet above the lava lake's surface, Tim Orr, a geologist at the Hawaiian Volcano Observatory, found something he had never seen before.
"It's kind of like a balloon,"Janet Babb, observatory geologist and public information officer, told The Huffington Post. "It's hollow inside with this thin, glassy shell, which is very fragile."
Scientists are calling it the "coolest Pele's tear" ever found -- a reference to the Hawaiian goddess of volcanoes and the tear drop-shaped glass particles that form when fountaining molten lava quickly cools.
The observatory wrote on its website that the "one-of-a-kind, completely hollow Pele's tear" is about half an inch in length and was likely ejected from the lava lake in the aftermath of the explosion, when the lake surface was spattering vigorously.
But the glassy object's fragile, egg shell-like structure has scientists scratching their heads.
“To my knowledge, it’s the only thing like it that has ever formed,” Orr told the Honolulu Star-Advertiser.
Rockfalls and subsequent explosive events, like the one seen above, are relatively common at the lava lake. They occur with no warning, sending fragments of hot lava, rocky debris and ash high into the air. The Friday event was the third explosion in a week, according to the HVO.
Babb told HuffPost there are many different kinds of fragments that come off the lava lake surface when it's spattering.
In addition to Pele's tears, ejected lava can form into golden strands of fragile volcanic fiberglass, which volcanologists call Pele's hair. There is also limu o Pele, Hawaiian for "seaweed of Pele," which are flakes or sheets of volcanic glass that form "when wind blows laterally through sheets of molten lava thrown up during the explosions."
Last year, the lava lake put on a spectacular show for Big Island residents and visitors when it overflowed several times. The event marked the first time the floor of Halemaʻumaʻu Crater had seen lava since 1982.
As for the recent, strange discovery, scientists are taking special care of it. Because the egg-like volcanic glass is too fragile to be handled, it will be kept in a display case in the observatory's lobby, which is not open to the public.
While other, much smaller "hollow spherules," as they are called, have been found, Babb says this piece is so special because of its size and that it somehow survived its flight out of the lava lake and onto the crater's rim.
"Something that fragile looking, you would think it would have broken into many pieces," Babb told HuffPost. "This is one of the things that makes science fun."
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