Tourmaline deposit in Sikait area (Southern Eastern Desert of Egypt [SEDE]) is closely associated with metapelitic schistose rocks that belong to Neoproterozoic time. The distribution of tourmaline was mostly controlled by Nugrus shearing, along with schist leucocratic rock varieties (leucogranite, pegmatite, and aplite dikes), which are syntectonically dissected by hydrothermal quartz veins. Local concentrations of tourmaline occur either as discontinuous tourmalinite bands/pockets or as disseminated isolated clusters of crystals within the metapelitic schistose rocks, pegmatites, and quartz veins. Chemical and mineralogical changes accompanying with tourmaline formation have been observed within the schistose rocks in contact with a pegmatitic bodies in Sikait area. Four mineral assemblages were identified on approaching to the pegmatite contact: (1) Quartz-Biotite-Potassium Feldspar-Chlorite assemblage (Q-B-K-C); (2) Quartz-Biotite-Tourmaline-Chlorite assemblage (Q-B-T-C); (3) Tourmaline-Quartz-Muscovite assemblage (T-Q-M); and (4) Tourmaline-Quartz assemblage (T-Q). Toward the pegmatite contact, K, Li, Rb, SiO₂, CaO, MgO, Sr, and Ba are decreased, while Al₂O₃, B₂O₃, Na₂O, Fe (tot), Zr, Y, and Th are moderately increased. Variations in the mineral assemblages and whole-rock chemistry within the four alteration zones appear to be controlled by boron metasomatism and potash leaching. The normalized rare earth element patterns of rock samples from the four alteration zones suggest a partial alteration of the original sedimentary patterns by the metasomatic-magmatic fluids. The alteration could be either a single phase of interactions between pegmatite fluid and schists with B-, Li-, Rb-carrying fluid or a couple of phases (B-, Mn-, Be-rich fluid and Rb-, Li-, K-rich fluid). In all cases, boron from the pegmatite-associated fluids reacts with the surrounding schistose rocks to breakdown of sheet silicate which acts as “traps” for Rb, Sr, Li, Ba, and K and hence leads to tourmaline-rich assemblages.

Sikait地区（埃及东南沙漠[SEDE]）中的电气石矿床与属于新元古代的变带片岩岩石密切相关。电气石的分布主要由Nugrus剪切作用控制，同时还有片岩白垩纪岩石种类（白云花岗岩，伟晶岩和云母岩堤），这些岩石通过热液石英脉共切。电气石的局部浓度要么以不连续的电气石带/袋出现，要么以变质岩片岩，伟晶岩和石英脉内散布的孤立晶体簇的形式出现。在Sikait地区，在片状岩石中与岩溶体接触时，观察到了电气石形成过程中化学和矿物学的变化。接近伟晶岩接触时，确定了四种矿物组合：（1）石英-黑云母-钾长石-亚氯酸盐组合（QBKC）；（2）石英-黑云母-电气石-亚氯酸盐组合（QBTC）；（3）电气石-石英-白云母组合（TQM）；（4）电气石-石英组合（TQ）。朝向伟晶岩接触，K，Li，Rb，SiO_2时，CaO，MgO，Sr和Ba减少，而Al ₂ O ₃，B ₂ O ₃，Na ₂O，Fe（总），Zr，Y和Th适度增加。四个蚀变带内矿物组合和全岩化学的变化似乎受硼交代作用和钾肥浸出控制。来自四个蚀变带的岩石样品的归一化稀土元素分布图表明，变质岩浆流体对原始沉积形态有部分变化。改变可能是伟晶岩流体和片岩与B，Li，Rb携带流体相互作用的单相，也可能是两相（B，Mn，Be富流体和Rb，Li，K -丰富的液体）。在所有情况下，伟晶岩伴生液中的硼与周围的片状岩石发生反应，使片状硅酸盐分解，这是Rb，Sr，Li，Ba和K的“陷阱”，从而导致电气石富集。