What does the tourmaline do?

Tourmaline is a unique stone with pyroelectric and piezoelectric properties known to generate negative ions upon heating or pressure.  

Every 4th line of Bio-Magnetic V-Mat surface is filled with natural black tourmaline, crushed to 3-9 mm size, and tumbled in drum machines to flatten any sharp edges. 

The other 75% of stones are natural amethyst.