Precipitous weakening of quartz at the α–β phase inversion. Issue 1 (24th September 2020)

• Record Type: Journal Article
• Authors: Lawn, Brian; Marshall, David; Raj, Rishi; Hirth, Greg; Page, Trevor; Yeomans, Julie
• Is Part Of: Journal of the American Ceramic Society. Volume 104:Issue 1(2021)
• Page Start: 23
• Page End: 26
• Publication Date: 2020-09-24
• Subjects: alpha‐beta transition -- deformation -- fracture -- quartz; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.17470
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: Crystalline quartz has long been identified as among the weakest of abundant crustal minerals. This weakness is particularly evident around the α – β phase inversion at 573°C, in which Si–O bonds undergo a displacive structural transformation from trigonal to hexagonal symmetry. Here we present data using indentation testing methodologies that highlight the precipitous extent of the transformational weakening. Although the indentations are localized over relatively small specimen contact areas, the data quantify the essential deformation and fracture properties of quartz in a predominantly (but not exclusively) compressive stress field, at temperatures and pressures pertinent to conditions in the earth's crust.