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.

中文翻译：

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α-β相变时石英的急剧弱化

长期以来，晶体石英一直被认为是最丰富的地壳矿物之一。这种弱点在573°C的α - β相转变周围尤为明显，其中Si-O键经历了从三角对称到六角对称的位移结构转变。在这里，我们使用压痕测试方法介绍了数据，这些方法突出了转型削弱的严重程度。尽管压痕位于相对较小的样品接触区域上，但数据量化了在与地壳条件有关的温度和压力下（主要（但非排他性））压应力场中石英的基本变形和断裂特性。