Samples of quartz glass detector have been irradiated vertically by 129Xe ions of energy 0.9 MeV/ N, 84Kr ions of energy 0.9 MeV/ N and 56Fe ions of energies 5.1 MeV/ N, 3.3 MeV/ N, 2.4 MeV/ N and 1.3 MeV/ N from the Joint Institute of Nuclear Research (JINR), Dubna, USSR. These irradiated samples have been etched in 40 vol.% HF at 30°C. The etch pit diameter against etching time has been measured and the total etchable track length has been determined for these ions in this detector. The energy loss and range of these ions in quartz glass have also been computed theoretically. Comparing the value of the total etchable track length with the theoretically computed value of the range, the critical threshold for etchable track formation in quartz glass has been found. An attempt to find the charge resolution of this detector has also been made.