The word isn't crystal. It's obviously a 6 letter word. Crystal is 7 letters. I think it starts of as "you can clear a way". Seeing as the word ending in "is" has two periods and the word ending in "stal" has two periods before it, the periods tell the number of letters in the word.

The only words that end in "stal" and are 6 letters long are "festal" "costal" "postal" "vestal" and "instal". Does anyone have any ideas about how to put it together?