Topaz of the Well

Pebble of Water. You can use an action to fill a container with fresh water using this gem. The gem can create up to 1 gallon of fresh water every 24 hours. To do so, speak a command word while touching the gem to a container that is not being worn or carried, such as a mug, glass, bucket, or barrel. The container is filled with potable water until it is either full or the gem reaches its daily limit.
  Waterbreather. While holding this gem in your hand, you can use a bonus action to gain the ability to breathe underwater. This effect lasts indefinitely, but you can only breathe water while holding the gem in your hand.