Menthol crystals are actually an all-natural extract of cornmint leaves. The oils crystalize into shard shapes that exhibit an intense aroma of menthol. They are used in many ways. They may offer assistance with things like airway and mite support. The can be added to a diffuser in times of stuffiness and congestion. They instantly dissolve in alcohol or essential oils. They may dissolve in oil and water at their melting point, although, when the water begins to cool, recrystallization occurs once more.