The 3/4 three quarter round basalt stone is perfect shaped to applied on the backside, stomach and lower back heat to relieve muscular tension, especially in the thigh area during hot stone massage treatment. Basalt rock material 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. We use natural Black Basalt rock as the only material, all stones were shaped and polished by traditional handcraft, no wax, dyestuff, chemicals were applied during the production. 10 pieces per pack. • Applies on the backside, stomach and lower back heat to relieve muscular tension, especially in the thigh area • The sharp edge all around is perfectly designed for Guasha massage • 100% Natural Black Basalt; Excellent for holding heat for long periods of time;Rich with iron and magnesium • Shaped and polished by traditional handcraft, no wax, dyestuff, chemicals were applied • Size: 3.8” x 3.2” x 1.1”, 2 Pieces per Box