An exceedingly small number of high‐pressure polymorphs have been discovered in lunar samples. This situation does not seem to reconcile with the prolonged, intense bombardment of the lunar surface, which should produce suitable conditions for the formation of such polymorphs. Here we report the discovery of reidite, a high‐pressure polymorph of ZrSiO₄ with scheelite structure in lunar meteorite Sayh al Uhaymir (SaU) 169. The reidite occurs mainly as lamellae hosted within zircon, likely corresponding to a deviatoric‐dominated transformation. The presence of reidite in the regolith portion of SaU 169 indicates a narrow temperature and pressure path constrained by the phase stability under low pressure and suggests heterogeneous shock features in the porous lunar regolith where the ambient temperature increases much higher than that in compact rocks. The inventory of high‐pressure polymorphs might be restricted by such unusual cooling processes lunar samples experienced.

中文翻译：

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在月球陨石Sayh al Uhaymir 169中发现Reidite

在月球样品中发现了极少数的高压多晶型物。这种情况似乎与长时间强烈撞击月球表面并不一致，后者应为形成这种多晶型物提供合适的条件。在这里，我们报告发现了Reidite（一种ZrSiO ₄的高压多晶型物）的发现。在月球陨石Sayh al Uhaymir（SaU）169中具有白钨矿结构。菱铁矿主要以锆石中的片晶形式存在，可能对应于偏斜为主的转变。SaU 169的碎屑岩部分中存在白闪石，这表明温度和压力路径较窄，受低压下的相稳定性约束，并表明多孔月球碎屑岩中的非均质冲击特征，其环境温度比致密岩石高得多。高压多晶型物的库存可能会受到这种异常的冷却过程所经历的月球样品的限制。