Variability of α/ß Inversion Temperatures of Natural Quartz

M. Blasy

Abstract: The inversion temperature of quartz at atmospheric pressure is 573 C. This temperature shows some variability caused by source of quartz, particle sizes, heating rate and pressure ( nitrogen atmosphere). The differential thermal analysis ( DTA) of natural hydrothermal and pegmatite quartz indicate that, 1- the inversion temperatures of both natural pegmatite quartz and natural hydrothermal quartz with the same particle size ( 0.1 mm) and the same heating rate (10 C /min. ) are 582.14C and 582.4 C respectively with small differences ( ~0.3C - 0.5C).2- by changing the rate of heating from 10 C / min to 15 C /min, the inversion temperature of pegmatite quartz changed from 582.14 to 584.60 C and hydrothermal quartz temperature changed from 582.40 C to 585.10 C with relatively large differences ( ~ 2.46C 2.7 C).3- by increasing the particle size of pegmatite quartz to 1.0 mm. at heating rate 10 C / min, the inversion temperature increased to 587.0 C.4- by decreasing the particle size of pegmatite quartz to 0.05 mm at heating rate 10 C /min. , the inversion temperature disappeared.5-The hydrothermal quartz not show thermal activity above the inversion temperature but the pegmatite quartz has thermal activity above the inversion temperature.

Keywords: Pegmatite, quartz, hydrothermal, DTA, inversion, heating rate, particle size