I like the pure and clear tone you set in the first couple of stanzas, but then with the 3rd and 4th stanzas, things become more heavy and less simplified.
I might add a word in the first stanza to replace "clear" so as to introduce another syllable there so there is not so sudden a stop with the words "for clear waters", especially if the thought is being continued in the next two lines. "Crystal" might be good, though maybe cliché. I might then move innocence (you have typo) to a fifth line and add a word for rhythm before it that serves an adjective or something. You just have such a nice alliteration and rhythm in "mocking the mask that belies" and "innocence" at the end of that stumbles it up.
I like the "eternal fires yet" in the second stanza, a good use of suspense in sound and an appropriate placement for that thought.
My suggestion would be to simplify the last two stanzas so that they have the same tone as the first two. The last two sound kind of like run-on sentences and loose the nice attention to speed and rhythm that you had started with. Get the last two stanzas down to their essenses and I think that would make this poem flow easier and leave some things, through subtle suggestion, to the imagination and create more intrigue.