As a geologist, there have been times in my life when I have been green with envy over the places
that other geologists get to travel to. They usually involve erupting volcanoes, but the Cave of Crystals
at the Naica mine, in Mexico, is one place that is high on my geology bucket list.
Discovered in 2000, this jaw-dropping cave has selenite (gypsum) crystals up to 12 meters in length!
The crystals have been formed over the last 500,000 years, from hot mineral-rich waters that filled the
cave until it was drained by the mine. Another cave - the Cave of Swords - is close by. Discovered in
1910, it too contains selenite crystals, but those are smaller at around 1 meter in length.
Conditions in the cave are dangerous - almost 60oC and over 90% humidity. The lucky few that have
been into the cave can only be in there for a matter of minutes. Any more than that and they run the risk over heating and even organ failure. Yet I'd be there in a heartbeat!
Crystals this large are extremely rare. Take out the people from a photo of the cave and you could be looking at a cluster of crystals that could fit in the palm of your hand. Amazingly, despite their size, the crystals are fairly delicate. Selenite is a soft mineral, easily scratched. And so the scientists that have been exploring the cave have to take extreme care not to damage them.
How long will this cave be accessible? It seems that the mine may be intentionally flooded again (it is
only the mine's pumps that are keeping the cave free of water). If this happens the crystals will be once again left to nature, perhaps to grow even more. Scientists today are therefore trying to gain as much information about the crystals as they can before this happens. So the pressure is on to explore the mine as much as they can now. All I can say to that is...lucky things!
This National Geographic video follows a team of scientists as they descend into what is perhaps the most amazing thing they have ever experienced.