This is just a short discussion about one of my favourite poems by one of my favourite poets, Robert Frost. 

Nothing Gold Can Stay by Robert Frost

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.

"On the surface" This usually refers to what we see or understand at "face value" or most superficially.

a liquid gold: this is a metaphor or abstract description and is not meant to be taken literally.

only lasts: the term to last is an estimation or measure of how long something remains or talks about how long something is useful for or is seen. It can also be a measure for how long something is effective for.  Example: "Most sunscreen protection only lasts for about two hours before it is no longer effective."

or so: this is a term used to estimate a the range of something.  Example: "I think I will need a week or so to finish the project."

taken the time: from the verb phrase to take time. It means to set apart some time to do something with intent.

a call: a term used to get someone's attention.  To bring something to the attention of a person.