A Hawaiian Volcano Observatory geologist has found what may be the coolest lava rock ever following a rockfall and explosion at Kilauea last week.

“It’s an incredibly curious thing,” said Tim Orr, a geologist with the observatory. “Nothing like this has been seen before.”

The black, glassy volcanic object is about the size and shape of a Pele’s tear — oval and about a half-inch long — but it is hollow inside, like a lava eggshell.

“The fact that it is hollow is what is really interesting,” Orr said.

Scientists posted a picture on the observatory website  Opens in a new taband initially described the object as the “Coolest Pele’s Tear ever!”

Pele’s tears are formed when small bits of molten lava in fountains quickly cool and form small, solid glass particles shaped like teardrops. They are often found at the end of a strand of Pele’s hair, which are thin strings of volcanic glass.

But Orr, who found the object Friday while collecting samples on the rim of Halemaumau Crater, said it may have been formed by a a process different from the creation of Pele’s tears.

“I have nothing else that I can call it,” Orr said. “I don’t know how it could have formed.”

Observatory scientists posted videos of the event Opens in a new tab that likely caused the object to form. A video, Opens in a new tab taken at about 3:51 a.m. Friday by a camera on the rim of Halemaumau, shows volcanic fragments shooting into the air after a section of wall fell into the lava lake on the crater floor, causing an explosion.

Volcanic rock fragments from the explosion flew about 360 feet to the rim of Halemaumau from the lake, about 100 feet below the crater floor.

The fragments range in size from dust-size particles to rocks more than a yard in diameter.

Orr speculates that the object may have formed after the initial collapse explosion, while the lava lake was still unsettled and sending spatter into the air.

“That it survived is pretty remarkable,” Orr said.

Janet Babb, public information officer at the observatory, said the object is “very small and quite fragile. One wrong touch and it could be in pieces.”

Orr said the object will be placed in a display case in the observatory lobby but will continue to be studied.

The lobby is closed to the general public, but school and other groups occasionally come to the observatory for educational visits and will be able to see it, Babb said.

Babb said similar lava bubbles have formed on cooling flows, but she’d never seen a bubble of lava detached from the flow.

“To my knowledge it’s the only thing like it that has ever formed,” Orr said.

“This is why we love science,” Babb said. “We’re trying to figure out the unknown.”