Emotional: Since lava is known for its grounding qualities, it's wonderful for calming the emotions. In fact,  the quality of fire springs from the ground, so in terms of healing gems, this lends itself to a calming but intense-energy. Because it comes from raw energy. It's considered to be a stone of rebirth and shedding unneeded layers of emotional attachment. 
Spiritual : Lava stones are fantastic for stabilizing and grounding the root chakra. This is because of the strong connection to the earth and its creationwithin the center of the Earth