riddle - I'm but a speck of fairy dust

A simple riddle of mine, focused towards meter and rhyme.

I'm but a speck of fairy dust
A glitt'ring jew'l, but only just
So small I scarcely can be seen
A trinity in me convenes

And yet without me you can't see
Fine art and words are made of me
I'm resolute; through me you can

View realms beyond the mortal ken

I shrink along with passing years
My number grows, I gain more peers
But treat me well 'tis very true
I sleep and live and die like you

Please include explanations for as many lines as possible in your answer.

Answer

You are:

A pixel

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I'm but a speck of fairy dust / A glitt'ring jew'l, but only just

Pixels are small and bright

So small I scarcely can be seen / A trinity in me convenes

RGB

And yet without me you can't see

You can't see content without them. Assuming specific to the context of its realm.

Fine art and words are made of me

Again, assuming the context of its realm.

I'm resolute; through me you can / View realms beyond the mortal ken

Pretty obvious, via the internet, games, etc.

I shrink along with passing years / My number grows, I gain more peers

DPI increases as computers get more advanced.

But treat me well 'tis very true / I sleep and live and die like you

"Sleep" possibly referring to monitor state, and pixels can die.