The strangest things in life happen in nature, as we’ve recorded numerous times on our Earthly Mission, and Romania is no exception. Trovants, a type of remarkable rock, grow, move, and even multiply, forming stunning structures.

The small village of Costesti is home to some rather bizarre geological formations — Romania’s sprouting stones. Locals have long been fascinated by the bulging bulbous boulders, which have inspired legends about the stones’ ability to expand and move, much like living organisms. Those legends, it turns out, are true.

The uneven spheroid shapes are thought to have been produced by the Middle Miocene’s extraordinarily long-lasting and strong seismic activity. Huge earthquake shockwaves crushed the sandy soils and concentrated the limestone cement into spherical lumps.

The looser sandstone surrounding these lumps wore away over time, exposing the denser trovants. (This isn’t always the case.) Some of the hundreds of documented trovants, found in at least 20 locations around Romania, were only discovered when the sand around them was chiseled away.)

What, on the other hand, causes these pebbles to grow, move, and multiply?

Trovants are formed by a hard stone core surrounded by sand or gravel. Only very porous sand quantities and sandstone deposits cemented by calcium carbonate-rich fluids can produce these unusual structures.

Calcium carbonate is necessary for the formation of a trovant, as well as for the growth of the rock when moisture is available. Trovants absorb the rain’s minerals, which then mix with the chemicals already existing in the rock, causing a reaction and increasing pressure inside. This pressure causes the stone to grow and multiply from the center to the edges, at a pace of around 4-5 cm per 1000 years.

Trovants are typically smooth and without edges, and can be cylindrical, spherical, or nodular in shape. The stones form these erratic shapes as they grow and multiply due to irregular cement secretion, and the same is accurate for their size, which ranges from a few millimeters to as much as 10 meters.

Trovants are unusual not only because of their structure and capacity to develop and proliferate. They are also capable of moving from one location to another. They also have root-like extensions and age rings evident when the stone is cut, as if that wasn’t enough. However, science still hasn’t figured out how to explain these peculiar characteristics.

It’s unclear if trovants should be classified as living or non-living animals because they plainly blend the properties of a plant and a rock. Whether alive or not, these growing stones are a magnificent sight to behold, and a must-see for anybody visiting Romania’s Valcea County.