Abstract
It has been found by the writers that, in the majority of cases, the decrepigraphs of quartz have a form similar to that shown in Fig., 3, which has three inflexion points where the rate of decrepitation increases suddenly., From microscopic observation of the heated samples of quartz, it has been interpreted that the popping at the first peak in the curve is produced by the breaking out of liquid inclusions., The third peak shows the cracking of crystals caused by the existence of cleavage and parting, volume change followed by transition, anisotropy of thermal conductivity and expansion, presence of solid inclusions, or lattice imperfections., And the second peak may be observed as superposition of the above-mentioned two kinds of sound., From these results, it has been found that, as the inflexion point at the beginning of the first peak can be taken to represent the temperature of complete filling of the inclusions with an allowance for possible overshoot, the decrepitation method may be used for measuring temperature of forming the inclusions instead of the heating stage-microscope method., However, in some cases when liquid inclusions are scarcely found in the sample, or when the sound produced by the breaking out of the liquid inclusion is too low to be detected, the inflexion point at the beginning of the second peak or the third peak may be in danger of being mistaken for that of the first peak.,
