I chose my same sensation to be the sense of change. I have an old, woodpecker loved cherry tree and this fall it is bleeding sap at a hugely increased rate. I also have an enormous amber necklace I bought 18 years ago on a choir trip through Europe when we were on the Baltic Sea in Poland. It is easy to see how, if I had "worlds enough and time" the sticky, flowing mass could emerge from being pressured and buried and become the gem.
I googled Amber Changing and expected to get some scientific info for you, but instead found lyrics to a song by that name
"These calloused fingers are wrapped around a black ball-point pen,
These eyes don't wander as far as they at one time did,
I've seen the future, it's fading faster
No place that I'd rather be than right here, right now
There's no time that I'd rather be than right here, right now
I'm on the other end begging you, pick up the phone,
A shaking whisper is answering:"don't call anymore"
Your voice is wasted 'cause i'm not listening
Freeze me in this moment, thaw me in ten years,
When the fires burned out and the smoke (clears)
No place that I'd rather be than right here, right now
There's no time that I'd rather be than right here, right now"
[ Lyrics from:
http://www.lyricsfreak.com/r/rise+against/amber+changing_20116633.html ]