Patent ID: 7427387

Claim:
A quartz powder which, upon heating from room temperature to 1,700° C., generates gases in which the amount of CO is 300 nl/g or smaller and the amount of CO 2 is 30 nl/g or smaller, wherein said quartz powder has a bulk density of from 1.3 to 1.7 g/cm 3 and a metal impurity content of 500 ppb or lower, wherein said quartz powder is a synthetic quartz powder produced by a sol-gel method, which comprises: (a) forming a silica gel by a sol-gel method; and (b) subjecting said silica gel to a heat treatment in an oxygen-containing atmosphere and subjecting said silica gel to contact with helium gas, wherein said subjecting said silica gel to a heat treatment in an oxygen-containing gas is carried out either before or after subjecting said silica gel to contact with helium gas.