For Tears of Sapphire Glaze (What am I?)

These doors are now open,
The truth lies within,
The emerald haze lifting,
...Again and again,

A monster inside,
That thou shalt not see...
A terrible lie...
And a bargaining plea...

These tears fall unsoundly,
Bursting from seams...
But now they call softly,
Goodnight and sweet dreams...