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柯石英是SiO_2的高压变种,在700～800℃时转变的压力是2.7～2.9GPa,因此柯石英和柯石英假象是用来确认超高压变质作用的标志矿物。到目前为止,柯石英和柯石英假象在西阿尔卑斯、挪威Caledonides、哈萨克斯坦、德国和前捷克的Saxonian Erzgebirge、波兰Sneznik山以及我国大别-苏鲁高压超变质带的榴辉岩及其他超高压变质岩中已有大量报道。这些柯石英多以单矿物包裹体的形式产出于石榴子石、绿辉石、蓝晶石、绿帘石、硬玉甚至白云石、电气石、氟磷镁石、锆石和金刚石中。柯石英的边缘常转化为栅状或细粒石英集合体,构成柯石英假象。环绕柯石英及其假象,主晶矿物常发育有放射状裂纹。Schertl等发现在Dora Maira超高压镁铝榴石石英岩的基质中有许多类似柯石英假象的栅状石英集合体,有些沿镁铝榴石边缘的裂隙与包裹于镁铝榴石中的柯石英外缘的栅状石英集合体连为一体,从而证明了粒间柯石英存在的可能性,但真正的粒间柯石英从未有过报道。
Coke is a high-pressure type of SiO 2, and the pressure of transformation is 2.7-2.9GPa at 700-800 ℃. Therefore, coesite and coesite are the illusion minerals used to confirm the UHP metamorphism. So far, coesite and coesite have been illusory in the Western Alps, Caledonides in Norway, Kazakhstan, Saxonian Erzgebirge in Germany and the former Czech Republic, the Sneznik Mountains in Poland and the eclogites and other ultra-high pressure Metamorphic rocks have been reported extensively. Most of these coesite occur in the form of single mineral inclusions in garnet, omphacite, kyanite, epidote, jade and even dolomite, tourmaline, fluorspiride, zircon and diamond. The edge of coesite quartz often transformed into a grid or fine quartz aggregate, forming coesite false impression. Around the coesite and its illusion, the main crystal minerals often develop radial cracks. Schertl et al. Found that in the matrix of the Dora Maira ultrahigh-pressure gabbro quartzite, there are many similar gravel-like quartz assemblages that are similar to coesite artifacts. Some fissures along the edge of the gabalite and coesite The outer periphery of the grid-like quartz aggregates as a single entity, thus demonstrating the possibility of intergranular coesite, but the real intergranular coesite has never been reported.