I know that you are very knowledgeable in geology/mineralogy, and my knowledge is limited. On my previous post, I included both types, as a general definition of the word "crystal".
But in that case, it appeared to me unlikely for a non soluble mineral, even slightly, to be present there in the form of a "shiny", non amorphous, inclusion, as, from what I have read, the inclusions in Jnats are generally formed from soluble "salts" that penetrate those naturally formed cracks that appear in the stones, like the ones in the above photo. With the water vaporizing, or dispersing by any means, some of those salts remain in the cracks, and with repeating cycles of this, and time, heat, with some reactions, the toxic inclusions are formed.
Again, I'm by no means an expert, as you can see, but it's a topic that interests me.