Scientists discover a new exotic mineral forged in the furnace of a Russian volcano

Volcanoes rank among the most destructive and majestic phenomena on the planet. But these fiery rifts do more than just destroy. They also create.

In a new study, researchers in Russia report the discovery of one such creation – an unusual mineral never before documented by scientists: a crystallized, vibrant, blue substance that the team called petrovite.

The mineral was found in the volcanic landscape of Russia’s Far East, atop the Tolbachik volcano on the Kamchatka Peninsula.

Blue cryptocrystalline crusts of petrovite. (Filatov et al., Mineralogical Magazine, 2020)

The eruptive history of Tolbachik dates back thousands of years, but in recent times two noteworthy events stand out: the “Great eruption of the Tolbachik fissure” of 1975-1976 and a second, minor follow-up which occurred between 2012-2013 .

The force of the eruptions during the first event tore up numerous cinder cones in the volcanic complex, opening up a rocky terrain that has since been discovered to be a rich vein of unknown mineral and fumarole deposits never seen anywhere else.

In total, Tolbachik volcano claims 130 type locality minerals that were first identified here, the latest being petrovite, a sulfate mineral that takes shape as blue globular aggregates of tabular crystals, many of which contain gas inclusions. .

The specimen studied here was discovered in 2000, near the second cinder cone associated with the 1975 eruption, and has been preserved for later analysis. It may have been a long time, but that analysis now reveals that this vibrant blue mineral exhibits unique molecular characteristics only rarely seen before.

The copper atom in the crystal structure of petrovite has an unusual and very rare coordination of seven oxygen atoms, “explains Stanislav Filatov, lead researcher and crystallographer at the University of St. Petersburg.

“Such coordination is characteristic of only a couple of compounds, as well as saranchinaite.”

Single grain of petrovite. (Filatov et al., Mineralogical Magazine, 2020)

Saranchinaite, identified a couple of years ago by another St. Petersburg team, was also discovered in Tolbachik and, like petrovite, has a striking color in its own right.

In the case of petrovite, the mineral, which is thought to crystallize by direct precipitation from volcanic gases, forms as blue cryptocrystalline crusts enveloping a fine pyroclastic material.

On a chemical level, petrovite represents a new type of crystal structure, although it bears similarities to saranchinaite, from which it could be produced, hypothetically speaking.

Notably, the molecular structure of petrovite – composed of oxygen, sodium sulfur, and copper atoms – is effectively porous in nature, demonstrating interconnected pathways that could allow sodium ions to migrate through the structure.

Because of this behavior, and if we can replicate the structure in the lab, the team believes this could lead to important applications in materials science, potentially enabling new ways of developing cathodes for use in batteries and electrical devices.

Crystal structure showing the sodium migration pathways. (Filatov et al., Mineralogical Magazine, 2020)

“At the moment, the biggest problem with this use is the small amount of a transition metal – copper – in the crystal structure of the mineral,” says Filatov.

“It could be solved by synthesizing a compound with the same structure as petrovite in the laboratory.”

The results are reported in Mineralogical magazine.