## 7 Conclusions  
The Jabal Sayid and Dayheen ring complexes provide valuable insights into the geological processes that govern the enrichment and segregation of rare metals, particularly in highly evolved peralkaline granites and associated pegmatities. In the Dayheen ring complex, the central part of the complex consists predominantly of monzogranites. Towards the outermost part of the complex, there is a transition to hornblende-biotite granites, followed by aegirine-riebeckite granite. This zonation of granitic rock types indicates variations in the chemical composition and evolution of the magmatic system within the complex. The Jabal Sayid granites, on the other hand, intrude into the Late Proterozoic volcano-sedimentary unit of the Mahd Group. The granites in this area are primarily peralkaline and are accompanied by a sheet-like pegmatite body.  
The evolution from an early granodiorite-diorite association to intermediate monzogranites and peralkaline granites with associated pegmatities can be successfully explained by the involvement of three different magma generations. During the early phase of underplating, which took place between 870 and 620 Ma, the first mafic magma was generated. This mafic magma led to the formation of the granodiorite-diorite association. This stage represents the first phase of magmatic activity associated with subduction. As tectonic processes continued, crustal thickening occurred, and the subducted oceanic plate broke away, leading to collisional magmatism (625-613 Ma). The deep parts of the overlying crust partially melted, and monzogranites were formed. During the post-collisional phase, which took place between 613 and 584 Ma, the crustal material underwent anatexis, i.e., the partial melting of the pre-existing rocks due to increased heat and pressure. This anatexis led to the formation of magmas that produced peralkaline granites and associated pegmatities through progressive chemical fractionation. This process can result in the enrichment of certain elements, including rare metals such as Zr, Y, Nb, REEs, U, and Th, in the residual melt. As the peralkaline granitic magmas underwent progressive chemical fractionation, they became increasingly enriched in these rare metals. The ascent of these magmas from deeper levels to shallower depths was likely facilitated by the Najd fault system. The interaction of the ascending magmas with surrounding rocks and fluids further influenced their composition and mineralogy. Fluids, such as aqueous solutions or volatile-rich gases, can contribute to the formation of highly fractionated pegmatities. These fluids can interact with the evolving magmas, causing further chemical differentiation and promoting the crystallization of rare-metal-bearing minerals within the pegmatities. The enrichment of rare metals within the Jabal Sayid and Dayheen peralkaline granites and related pegmatities can lead to the development of economically significant mineral deposits, making them of interest for mineral exploration and extraction.  
Methodology, H.H.A.E.-N. and Y.H.D.; formal analysis, H.H.A.E.-N. and Y.H.D.; investigation, H.H.A.E.-N. and Y.H.D.; resources, H.H.A.E.-N.; data curation, Y.H.D.; writing--original draft, H.H.A.E.-N.; writing--review and editing, H.H.A.E.-N. and Y.H.D.; visualization, H.H.A.E.-N. and Y.H.D.; supervision, Y.H.D.; project administration, H.H.A.E.-N.; funding acquisition, H.H.A.E.-N. All authors have read and agreed to the published version of the manuscript.  
This research work was funded by Institutional Fund Projects under grant no. (IFPIP-1441-145-1443).  
Not applicable.  
The data presented in this study are contained within the article.  
The authors gratefully acknowledge technical and financial support from the Ministry of Education and King Abdulaziz University, Jeddah, Saudi Arabia. We would like to express our gratitude to the reviewers for their valuable comments and suggestions, which have greatly contributed to improving the quality of this manuscript.  
The authors declare no conflict of interest.