Cave blisters are hemispherical bulged speleothems formed by a capillary water under pressure fed from an orifice in the wall, starting from a small bud with the encrustation being forced away from the wall by subsequent crystallization. In Provalata Cave they are few centimeters in size, built of gypsum, and probably other minerals, deposited due to evaporation of the feeding capillary water, with the mineral heterogeneity partly responsible for the cracking open of the blisters.