We found how an extremely rare crystal was created on Mars  

It has puzzled scientists for years

In 2016, the Curiosity rover discovered a very unusual crystal in Gale Crater on Mars. This mineral is very rare on Earth, but in Gale Crater it was found in huge quantities. The reason for tridymite, a crystal that forms only under very high temperatures, like those of magma. Although Mars has proven to us that it had volcanic activity in the past, the Gale Crater is not located in these areas and we think it was once full of water, leaving scientists puzzled as to the creation of the crystal.

A team of researchers from Rice University finally solved the mystery. So they found that tridymite came from a single volcanic eruption 3-3.7 billion years ago.

The discovery of tridymite in a mudstone in Gale Crater is one of Curiosity’s most unexpected observations in the last 10 years it has been exploring Mars. Tridymite is usually associated with developed, explosive volcanic systems on Earth, but we found it at the bottom of an ancient lake on Mars, where most volcanoes are very primitive.

Tridymite forms at temperatures exceeding 870 degrees Celsius and transforms into cristobalite at 1,470 degrees Celsius. Both minerals were discovered in the same location.

The researchers concluded that a magma chamber existed beneath the lake long enough for it to cool and crystallize. When it suddenly exploded, it scattered the tridymite into the air and fell back to the ground, raining into the lake.

It is practically a direct evolution of the rest of the volcanic rocks that we find in the crater. We say this because we only saw this mineral once and it was in high concentration in a single layer, so the volcano erupted when the lake was already there.

This shows that Mars has a more complicated volcanic history than we know. Future missions will look for other evidence of volcanic activity to understand exactly what happened on Mars.

The research was published in Earth and Planetary Science Letters .