5000 Year Old Christmas Present for Jenolan Caves

Recently, here at Jenolan Caves, we received a package in the post. In it, we found a 16 cm long piece of sparkling crystal – a stalactite – thickly swaddled in bubble wrap. The accompanying letter revealed that it had been broken off by a visitor to Jenolan, 2 years ago. The sender apologized sincerely for the vandalism perpetrated by her daughter’s irresponsible boyfriend, and she sent it back to us. It was signed ‘A Mother Who Believes in Honesty’.

We were moved almost to tears, to think that someone cared enough to return the crystal to us.

Jenolan Caves are approximately 340 million years old, formed by water flowing through limestone, creating around 40 km of labyrinthine passages and huge caverns. Over millions of years, the underground river carved its way downwards through the limestone. As uppermost caves became dryer, yet moist and humid, deposits of dissolved limestone began to crystallize into formations, such as stalactites. Therefore, the uppermost caves contain the biggest and most ancient stalactites and other speleothems.

It is said that stalactites grow an average 1 cm per 100 years. That is a very rough average and can vary enormously, depending on the amount of moisture present in the cave environment. Our piece of stalactite has taken at least 2,500 years to grow - probably more like 5,000 years or more.

The base of the piece of stalactite (where it was broken off) enables us to see that the crystal grew in distinct stages. The time between each stage cannot be measured. If we had access to the latest technology, we could get a more scientific estimate of its age. However, we can make educated guesses as to what happened. 

• It started with clear moisture moving with immeasurable slowness, down to the end of an existing stalactite or limestone surface, where it gathered in a droplet and deposited a particle of dissolved limestone, which crystalised. After 10 cm of growth (say 1000 years) of this process, the water source stopped, perhaps due to earth movement. 
• Unknown years passed. Maybe 100. Maybe 10,000. Who knows? Then, moisture from a different source, containing a red mineral, possibly iron oxide, began to gather on the older crystal, forming an orange layer of newer crystal – another 5 cm of growth – 500 years. Then, that water source stopped also.
• Again, unknown years passed. Clear moisture again began to gradually form another 5 cm of newer pale crystal – 500 years.
• Next, something happened (maybe more earth movement or a flood) which caused approximately 10 cm of the tip to break off. Regrowth took another 500 years at least.

Altogether, it would not be exaggerating to say that the 16 cm piece of crystal took 5,000 or more years to grow. It was probably there when Egyptians started building pyramids. And guess what - the piece that was returned to us appears to have been broken off the end of a bigger stalactite, thousands of years older!

At Jenolan, we do our best to protect every cave formation. But protection was not always in place. For 34 years after European settlers found the caves, it was common for visitors to ‘souvenir’ the formations. Today, you can see where crystal has been stolen from the uppermost caves. Fortunately, in 1872, the practice was made illegal. So, the deeper caves, discovered after that date, still have almost all of their fabulous crystal formations intact.

There have been rare occasions when pieces of crystal have been returned to Jenolan, along with notes alluding to bad luck they have experienced since they stole it. But the story of this particular piece gave us a warm and fuzzy glow, and we really appreciate the sentiment behind the gesture.

Long before the very first Christmas, this treasure was growing ever so slowly in profound darkness and stillness. And having been suddenly wrenched away, has now been returned home – an early Christmas present.