Two comments:
1- Maybe if they squish it hard enough they can make it transparent, like on one of the Star Trek movies.
2- This reminds me a bit of “Ice Nine”, exploring phases of materials which have surprising properties... and in the case of Ice Nine, consequences.
One of the theings that bothered me about that story is that he never seems to take into account that we are mostly bags of water when you get right down to it.