Black Lava Stone

Grounding•Calming•Anxiety 
Lava stone is said to alleviate anxiety, promote emotional tranquillity and bring calmness and feelings of relaxation. 
Lava stone is supposed to have very powerful spiritual effects on the human mind. It's said to cleanse negative thoughts and emotions, as well as stimulate creativity. Very grounding.
They are porous with “craters” on them. You can drop one drop of oil on each bead (a little goes a long way, so you only have to put them on a couple of the beads) and it will last 2-3 days.