Magnificent petrified gas bubbles
When we observe a volcanic eruption, what seems to us to be merely liquid rock actually contains solid crystals and gas bubbles.
These images show gas bubbles that were filled with secondary minerals during or following the cooling of the lava.
The secondary minerals are not part of the lava itself, but derive from its alteration or from external sources.
They can derive from the hot water of a geyser or from rain water heated by the basalt that has not yet cooled.
These bubbles often maintain their spherical shape, but the minerals that have filled them have rays and fans; “bushes” of needle-shaped crystals.
In these rocks, the spherical bubbles have diameters of one to just a few millimetres, and can only be observed under a microscope.
Very rarely, these fans of needle-shaped crystals fill larger cavities, and in these cases they are highly sought-after by collectors.
|Type of rock:||Effusive magmatic rock|
Pyroxenes, olivine, plagioclase, magnetite. Calcite, serpentine and zeolites as alteration minerals
|Location:||Pannone (N 45° 53′ 12.4″ E 010° 55′ 00.3″)|
|Formatione:||Basalt of the Val Lagarina|
Middle Ecocene (56-38 million years)
|Depositional environment:||aerial or submarine lavas, filling of superficial fractures.|