Cleansing crystals with water, taking crystals into the bathtub, or putting crystals in your drinking water can be beautiful practices, but not all crystals should be submerged in water! Some will get damaged and others can actually be harmful to you.
To get technical for a moment, take a peek at the Mohs hardness scale. At the softest end is talc, at 1. At the hardest end is diamond, at 10. Only crystals with a rating of 6 or higher are safe to cleanse with water. Those with a lower Moh's hardness rating, like selenite, which sits at a 2, can actually begin to dissolve or crack in water.
Other crystals you should keep out of the tub are those containing iron (like pyrite and hematite) which can rust or discolor, and those containing copper (such as azurite and turquoise), which can emit toxic gasses when wet. If a crystal is particularly porous (like ) it likely shouldn't go in water, either.
Aren't you glad you googled this before you brought your crystals into the bath?
Crystals you should not put in water
These crystals should never go in water:
Actinolite - contains asbestos; toxic if ingested
Amazonite (6-6.5) - contains lead; toxic if ingested
Angelite (3.5)
Apatite (5)
Azurite (3.5-4)
Calcite (3)
Celestite (3-3.5)
Chrysocolla (2.5-3.5)
Desert Rose (1.5-2)
Fluorite (4)
Gypsum (2)
Hematite (5.5-6.5)
Kyanite (4.5)
Larimar (4.5-5)
Lapis Lazuli (5-5.5)
Lepidolite (2.5-3)
Malachite (3.5-4) - toxic if ingested
Moonstone (6) - can break or be damaged
Opal (5.5)
Pyrite (6-6.5)- can rust or discolor & is toxic if ingested
Rhodochrosite (3.5-4)
Selenite (2)
Sodalite (5.5-6)
Talc (1)
Turquoise (5)
*Note that many of these end in 'ite', so take caution when using crystals with this suffix.
Crystals you can put in water briefly (or carefully)
These crystals can be rinsed with water but shouldn't be submerged for longer periods:
Black Obsidian (5-6)
Labradorite (6-6.5) - Completely avoid salt water
Moonstone (6-6.5)
Crystals that are safe to go in water
Feel free to take these water-safe crystals into the bath with you:
Agate (7)
Amethyst (7)
Aventurine (6.5-7)
Carnelian (7) - not safe in saltwater
Citrine (7) - not safe in saltwater
Clear Quartz (7)
Herkimer Diamond (7)
Jasper (6.5-7)
Melody Stone (aka Super Seven) (7-7.5)
Rose Quartz (7)
Ruby (9)
Rutilated Quartz (7)
Sapphire (9)
Smokey Quartz (7)
Tiger's Eye (7)
Topaz (8)
While the list of you crystals you can't put in water is pretty extensive, you can still enjoy their healing properties by placing them around the tub or next to your drinking water.
If you love working with crystals, bookmark this page for easy reference next time you want to take a crystal bath.