Crystals that are NOT suitable for placing in water / making gem water
This list will explain common stones that are either toxic to use for drinking in gem water or stones that are soluble in water. :)
Alunite: Non toxic but soluble in water
Anglesite: Toxic and slightly soluble in water
Arsenopyrite: Potentially toxic
Azurite-Malachite: Harmful
Azurite-Pseudomalachite: Harmful
Bunsenite: Toxic; allergen; avoid skin contact
Calomel: Possibly hazardous to health
Chalcanthite: Harmful; easily soluble in water
Cinnabar-Opal: The cinnabar stored in the opal is toxic
Durangite: Potentially toxic
Eclipse Stone: Limestone with orpiment, toxic
Erythrite: Potentially toxic
Fluorite, Antozonite variety: Potentially harmful
Galenite: Toxic and slightly soluble in water
Gaspeite: Harmful; allergen; avoid skin contact
Halite: Not toxic in small quantities, but dissolves easily in water
Iron-nickel Meteorite: Harmful; allergen; avoid skin contact
Jamesonite: Potentially toxic
Lemon Chrysoprase: Potentially harmful; allergen; avoid skin contact
Lopezite: Very toxic! Hazardous even through skin contact
Millerite: Toxic; allergen; avoid skin contact
Nickeline: Toxic; allergen; avoid skin contact
Olivenite: Potentially toxic
Proustite: Potentially toxic
Psilomelane and Pyrolusite: Harmful
Pyromorphite: Potentially toxic
Realgar: Toxic. Store in dark, securely locked place.
Scorodite: Potentially toxic
Sphaerocobaltite: Harmful; allergen; avoid skin contact
Tetrahedrite: Potentially harmful
Ulexite: Non toxic but slightly soluble in warm water
Valentinite and Senarmontite: Harmful
Wulfentie: Potentially toxic