Basalt rock is originally found deep within a volcano where it remains for hundreds of millions of years, gaining all of its natural properties. All Basalt is rich with iron and magnesium, which make this stone very effective in massage treatments. Basalt is excellent for holding heat for long periods of time and has very low radiation which makes this rock a much more healthy and beneficial stone for use. More therapists prefer to use our large Flat Ovular Basalt for the thigh muscles instead of our medium sized Ovular Basalt Stones. The larger Flat Ovular Basalt stones and 4 pressure point stones are ideal for massaging the backside and neck massage, especially after a long day of using computers. It's suitable for a 2 hour full body massage. The natural bamboo box is handmade to provide an efficient storage place for your stones.