Correlation Between Knoop Microhardness and Amsler Abrasive Wear in Ornamental and Cladding Rocks

Objective: The main objective of this study is to correlate the results obtained from Knoop microhardness and Amsler wear tests performed on different types of ornamental stones. Theoretical Framework: Mechanical properties, especially hardness, are essential parameters in the technological characterization of ornamental stones, as they reflect their behavior under abrasive forces and industrial processing. The correlation between hardness and wear resistance depends on mineralogical composition and texture, highlighting the importance of standardized studies to optimize the technological use of these materials. Method: The study involved 41 lithotypes of ornamental stones tested at CETEM-NRES. For each sample, Knoop microhardness and Amsler wear tests were performed. Microhardness, according to the BS EN 14205 (BSI, 2003) standard, was determined with up to 80 indentations per stone. The Amsler wear test, following NBR 12042 (ABNT, 1992), evaluated thickness loss after paths of 500 and 1000 m. Results and Discussion: The results showed a wide variation in Knoop microhardness among the 41 lithotypes, associated with mineralogical and textural differences. Igneous stones exhibited higher hardness, while metamorphic and sedimentary stones showed more heterogeneous values. A significant correlation was observed between microhardness and wear resistance, confirming microhardness as an effective parameter for the technological evaluation of ornamental stones. Research Implications: This study contributes to improving the technological characterization of ornamental stones by providing more accurate parameters to predict their wear behavior. Originality/Value: The research correlates Knoop microhardness with wear resistance in ornamental stones, proposing an innovative approach to assess mechanical performance and support the selection of more durable materials for civil construction.