The rock cycle is a natural process that recycles Earth’s materials, and metamorphic rocks are a key part of this cycle. Their transformation gives us clues about Earth’s deep history and provides us with valuable materials. Lithology is a critical factor in reservoir evaluation, typically assessed through core recovery in the laboratory. However, this process is costly and its interpretation is time-consuming. Accurate lithology identification using geophysical log data is essential. Pattern recognition and statistical methods are powerful tools for this task. This article introduces the Z-number-based clustering. The advantage of this method is expressing reliability of the information.