Nature’s first green is gold,
Her hardest hue to hold.
Her early leaf’s a flower;
But only so an hour.
Then leaf subsides to leaf,
So Eden sank to grief,
So dawn goes down to day.
Nothing gold can stay.
by Robert Frost
I love Robert frost. Great poet.
Nothing gold can stay in this era/age/aion. Next one is another day. 
I too love Robert Frost – Brilliant!