###### Abstract  
This study focuses on the petrographic and geomechanical properties of the Inzari Formation rocks in Tar Khel Village, District Swabi, Khyber Pakhtunkhwa, Pakistan, on their suitability as building materials for structures such as bridges, buildings, and roads. Five fresh samples from various areas of this formation were analyzed and identified as siliciclastic mudstone through petrographic analysis. The results of physical properties (water absorption, specific gravity, and porosity) and mechanical properties (unconfined compression strength, unconfined tensile strength, Schmidt hammer test, and shear strength) indicate the Inzari Formation rocks have unconfined compressive strengths ranging from 23 to 94 MPa, specific gravity values \(\geq\)2.78, and low porosity and water absorption values (\(<\)1%), suggesting their excellent potential as building materials. Comparatively, the unconfined compressive strength values of the Inzari Formation rocks are similar to those of the NikianSchar limestone, which averaged 93.348 MPa, further confirming their suitability for construction. Additionally, the low porosity values of the Inzari Formation rocks align with the porosity range of 0.31% to 0.41% reported in the NikanSchar limestone study. Based on these findings, the Inzari Formation rocks are appropriate for use as fine aggregate in concrete, asphalt, and other construction materials. Inzari Formation; petrographic analysis; geomechanical properties; unconfined compressive strength; construction materials; specific gravity +
Footnote †: journal: Medical  
of rocks. The term 'index properties or parameters that govern the composition of rock to support its classification' refers to the physical characteristics of rock. The mechanical feature referred to as strength comprises the parameters or attributes that tell us about a rock's strength and durability under specific circumstances like humidity, temperature, and loading conditions. In addition to the rock's inherent physical and chemical characteristics, non-technical methods of rock excavation used in the construction industry have an impact on the strength of rock. The properties of building materials differ based on the kind of rock and are significantly impacted by the processes involved in the creation of rock in addition to the outside influences that exist all through the rock's metamorphism [6]. A geologist is needed to assess the characteristics and quality of rock during extraction and to determine whether it will be feasible to use it for a particular construction project. As a result, evaluating an aggregate's quality is crucial to deciding whether or not it can be utilized for engineering purposes [7]. It is required to subject rock aggregates to a variety of tests in accordance with international and local regulations in order to determine their suitability for any engineering-related purpose. These tests include the uniaxial compressive stress test (UCS), tensile strength, Brazilian test, Schmidt's hammer test, point load index (PLI), SD test, total core recovery (TCR), and rock quality designation (RQD), in addition to testing for porosity, water absorption, specific gravity, and density. The nature of rock often is examined using microscopic analysis (polarizing and scanning electron microscopes) and physical and chemical studies. In addition to being utilized as building materials, rock aggregates are employed in the construction of railways, roads, and dams, as well as for concrete aggregate and asphalt base courses. As a result, a lot of academics have attempted to investigate how certain petrographic and rock fabric characteristics affect the mechanical qualities of rocks [8]. Rock fabric and petrographic factors such as grain size, form, degree of cementation, type of cementation between grains, and mineralogical composition all affect mechanical properties. Soil and rocks are the two categories of earth materials that are studied in engineering geology [9].