Under normal pressure, the quartz crystal with the temperature difference of five different nature of the variants, namely:

(1) α quartz, its temperature is below 573 ℃ when the steady state, that is, we usually use the piezoelectric quartz crystal.

(2) β quartz, α quartz heating over 573 ℃, that is converted to β quartz, it is 573 ℃ ~ 870 ℃ between the steady state, but this time there is no piezoelectric effect, can not be used as piezoelectric element Device.

(3) phosphorus quartz, when the β-quartz heating more than 870 ℃, β quartz into phosphorus quartz, it is between 870 ℃ ~ 1470 ℃ steady state.

(4) square quartz, when the phosphorus quartz heating more than 1470 ℃, the phosphorus quartz into square quartz, it is between 1470 ℃ ~ 1710 ℃ stable

(5) quartz glass, when the other side of the quartz heating more than 1710 ℃ and after the beginning of melting, melting quartz, the temperature can not be reduced

   Five forms can be found in the following formula:

        573 ° C 870 ° C 1470 ° C 1710 ° C

 Α quartz → β quartz → phosphorus quartz → square quartz → quartz glass

  It can be seen that the critical temperature of α-quartz is 573 ° C. If this temperature is exceeded, it will lose the piezoelectric effect, which is the problem that we must pay great attention to in the process.