## 1 Introduction  
Norite is a plutonic igneous rock primarily composed of plagioclase feldspar and pyroxene minerals. It is formed through the slow cooling of magma deep within the earth's surface, creating a strong and durable rock. The use of norite is extensive within the engineering space due to its compressive strength, resistance to abrasion, and stability. In civil engineering, it is preferred as a road aggregate and is used in foundational work, whereas in mining, it is frequently contained in mineral bearing resources such as chromitite and platinum group elements (PGMEs), amongst others, with a higher proportion of orthopyroxene. In South Africa, norite in the Bushveld Igneous Complex (BIC) is identified as having a shear plane of weakness within confined regions of the rock, which can vary in continuity depending on the applied stress conditions [1]. Shear planes can either be continuous, extending smoothly across the material, or discontinuous, breaking into segments, depending on factors such as the material properties, stress conditions, and the presence of pre-existing weaknesses [2]. A study by [PERSON] et al. [3] (2020) reported norite as an igneous rock comprising low titanium dioxide concentrations (0.1-0.7 wt% TiO\({}_{2}\)), high bulk rock magnesium (0.57-0.83 wt% Mg), and high silica contents (52-60 wt% SiO\({}_{2}\)). According to [PERSON] et al. [4] (2018), a rock is considered norite if it contains both primary pyroxene and plagioclase with the prefix leuco applied when the rock consists of 65% to 90% of plagioclase. The eastern bushveld complex norite, particularly above Upper Group 2 (UG-2), is crucial in engineering and mining due to its strength. However, the fractures that occur in norite that act as weak planes can impact mining excavation, highlighting the need to understand rock strength based on its mechanical properties and mineralogical content [1]. [PERSON] et al. [5] (2016) also outlined the importance of norite as it has the potential to be used as a solid precursor in the creation of a new cementitious binder since it contains a higher concentration of plagioclase than quartz. Stratigraphically, norite is found in the Critical Zone of the BIC, which is the most economically valuable zone and serves as the boundary between ultramafic rocks (harzburgites and pyroxenites) and mafic rocks (norites and gabbronorites) [1]. Comparing the mechanical and petrographic properties of norite helps geologists and rock engineers understand its behavior under different conditions. Mechanical properties such as strength and elasticity define how rocks react to stress and environmental conditions [6]. [PERSON] et al. [7] (2022) provided a factual justification for petrographic analysis importance based on the mineral composition and texture of rocks, offering insights into their formation and behavior. Therefore, it is critical to comprehend the importance of the mechanical and petrographic properties of a rock in order to effectively determine the appropriate method to estimate its brittleness. [PERSON] et al. [7] (2022) also emphasized that both short-term and long-term rock behavior can be assessed by considering the interaction of various parameters, such as rock texture and petrophysical and mechanical properties, which are essential for many geoengineering applications. The brittleness of the rock is a key property in determining how the rock breaks or fractures. Moreover, brittleness is an important mechanical attribute of rock masses and a key parameter for evaluating hydraulic fracturing, rock breakage, and explosions [8]. [PERSON] et al. [9] (2023) also circumstances the brittleness index as an empirical mechanism parameter to evaluate rock brittleness, which is crucial for resource exploitation, mechanical efficiency, rock burst prediction, and disaster prevention. Consequently, it is worth exploring the applicability of norite to dynamic loads wherein brittleness indexes measure the propensity of a rock to break or fracture under stress rather than undergo plastic deformation [9].