I have tried to avoid picking up the snowflake, because having it account-bound is a feature I personally dislike. But this time I had to finally pick it up, because the only way to the portal was "blocked" by it.

So my question is this:

What will happen, if I destroy my snowflake? Will it start to reappear on the islands again, or will it vanish forever for me?

P.S. Meanwhile I have managed to turn my snowflake into etelia, but my above question still stands. If I destroy my etelia, will the snowflake reappear on the islands or not?

Snowflakes and wild born Etelias are one per account. You won't be able to find another one if you decide to destroy your Snowflake or send away the Etelia born from it.