Sourced from: Japan
Enhydro visibility: Medium
"Enhydro agates are made up of banded microcrystalline or cryptocrystalline quartz. The agate has a hollow centre, partially containing water because the cavity is not full, the agate can produce sound from being shaken.
Enhydros are formed when water rich in silica percolates through volcanic rock, forming layers of deposited mineral. As layers build up, the mineral forms a cavity in which the water becomes trapped. The cavity is then layered with the silica-rich water, forming its shell. Unlike fluid inclusions, the chalcedony shell is porous, allowing water to enter and exit the cavity very slowly.
The water inside of an enhydro agate is most times, not the same water as when the formation occurred."