Halite

Halite is a sodium chloride (NaCl) crystal and as such, is soluble in water. Unless using as a bath soak (it's reusable until dissolved) keep halite dry.

"Studies show nanosized halite to be the second phase after aragonite that may primarily be deposited in a coral skeleton. " (Motai et al., 2016)

Licking or ingesting raw halite in the "wild" could cause health problems due to unidentified admixed substances (such as alkaline compounds).