NaCl.

You have NO idea how long this shot has taken.
It's one of my "Just in case" shots I take multiseveral of on a regular basis.
Manymany moons ago we bought some of that much vaunted Himalayan (pink) salt. Just coz I'm me I had to make a concentrated solution, which turned out to be absolutely clear with a pink sludge on the bottom. Be that as it may I thought I'd try and grow some crystals, these are the best four: currently about 3-5mm on a side.
Thing is I've yet to see any crystals which may prove to be other than NaCl, I'll keep watching.
Now I just wish I'd taken note of the date.
If this is ever repeated I'll stick in a coin for size comparison.