Micas are the most common hosts of lithium in granitoid igneous rocks. Unfortunately, their Li contents cannot be determined by electron-probe microanalysis (EPMA) which is the most common method of mineral analysis. In an effort to avoid the use of other, technically more complex and expensive methods, several empirical schemes for the estimation of Li-contents from EPMA data have been developed. The methods proposed by Tischendorf (Mineralogical Magazine, 1997) have found the widest application. After 25 years of common usage, we have evaluated these methods by direct Li determination using laser ablation-inductively coupled plasma-mass spectrometry (LA–ICP–MS). Approximately 3000 spot analyses of Li in micas from eight areas worldwide obtained by LA–ICP–MS were compared with the values yielded by the methods of Tischendorf. We conclude that none of the lithium estimation methods can compensate fully for a real local analysis by LA–ICP–MS or secondary-ion mass spectrometry (SIMS). Generally, SiO2-based estimation for trioctahedral micas provides a better match to the analysed values than F-based estimation for dioctahedral micas. The Rb-based estimation for dioctahedral micas does not provide acceptable results. The usage of averaged Si- and F-based estimations can be accepted in common petrological studies for a general characterisation of mica species. Large errors of individual spot estimations preclude their usage in detailed mineralogical studies.

云母是花岗岩火成岩中最常见的锂宿主。不幸的是，它们的锂含量无法通过电子探针微量分析（EPMA）来测定，而电子探针微量分析是最常见的矿物分析方法。为了避免使用其他技术上更复杂和昂贵的方法，已经开发了几种根据 EPMA 数据估算锂含量的经验方案。 Tischendorf（矿物学杂志，1997）提出的方法得到了最广泛的应用。经过 25 年的普遍使用，我们通过使用激光烧蚀-电感耦合等离子体质谱 (LA-ICP-MS) 直接测定 Li 来评估这些方法。通过 LA-ICP-MS 获得的来自全球 8 个地区的云母中约 3000 个锂点分析结果与 Tischendorf 方法得出的值进行了比较。我们的结论是，没有一种锂估算方法能够完全补偿 LA-ICP-MS 或二次离子质谱 (SIMS) 的真实局部分析。一般来说，三八面体云母的基于 SiO 2的估计比二八面体云母的基于 F 的估计提供了与分析值更好的匹配。基于 Rb 的双八面体云母估算未提供可接受的结果。基于平均 Si 和 F 的估计的使用可以在普通岩石学研究中被接受，用于云母物种的一般表征。个别地点估计的巨大误差妨碍了它们在详细矿物学研究中的使用。