Transitions, change and the passing of time:
Delta
Inside Prometheus Cave
Any material which is soluble, can be deposited as a colloid or is in suspension, or is capable of being melted, may form a stalactite. Calcium Bicarbonate solution travels through the rock until it reaches an edge and if this is on the roof of a cave it will drip down. Over time a stalactite will form. An average growth rate is 0.13 mm (0.0051 inches) a year, so these speleothems mark a long passing of time.
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jim holroyd 365 
Exquisite color transition, too.
thanks
You have reminded me of my days as a guide in the Cango caves during holidays when I studied. I was good at pinning down the age for formations. For instance I told tourists that the flowing waterfall is a million and 2 years old. I started working at the caves 2 years ago and then they told me it was a million years old…
that is a funny story, did they believe you?
They way I said it was designed to make them understand that I am joking (but those who didn’t get the joke probably believed it!). At the very spotsame I blundered when I wanted to say “behind you” the first time (English is my 2nd language). I said: towards your backside…
What a beautiful cave, and picture too!
Thank you, Carlos. There are many caves in Georgia, these were only discovered in the 1980s, I believe.