Abstract: The abrasive material contains Fe, Si, Ca, Al, Mg and Mn and has an amorphous continuous phase, wherein the total amount of Fe, Si and Ca is 50.0% or more by mass in terms of the total content of FeO, SiO2 and CaO, Fe is contained in an amount of 6.0% to 35.0% by mass inclusive in terms of FeO content, Si is contained in an amount of 15.0% to 35.0% by mass inclusive in terms of SiO2, and Ca is contained in an amount of 10.0% to 35.0% by mass inclusive in terms of CaO content, wherein all of the amounts are those relative to the entire amount of the abrasive material.

Abstract: A chair-type massage machine is provided which is adapted to give a twisting massage to the upper half of the body of the user. The massage machine comprises a seat 12 for the user to sit in, and a backrest 20 disposed at a rear end of the seat, the backrest being provided with a pair of opposite therapeutic air bags 30, 32 for massaging the back of the user. The pair of opposite therapeutic air bags 30 32 are arranged in a V shape and spaced apart by a large distance at an upper side of the backrest 20, the distance decreasing from portion to portion downward.