3 forms of Gypsum vs 4 years of sitting in water I did this to show gypsum does not dissolve immediately if not ever. Water can weaken the structure overtime (as it has started to this year) but it will NOT ‘dissolve.’ Contrary to what these crystal blog posts will regurgitate ALL of your crystals are literally pressure washed before coming to you, dowsed in chemicals to get the iron stains out and then carved/polished under a stream of water. MOHS SCALE OF HARDNESS DOES NOT DETERMINE WATER SOLU