epäkivi

Epäkivi is a Finnish term used in geology and mineralogy to describe a rock or mineral that exhibits properties or a composition that deviates from the expected or typical for its classification. It essentially means "false stone" or "pseudo-stone" and is often applied when a sample initially appears to be one type of mineral or rock but is later identified as something else, or possesses unusual characteristics.

This term can be used in various contexts. For example, a mineral might be misidentified due to superficial similarities in appearance to a more common mineral, but its chemical composition or crystallographic structure proves it to be different. Alternatively, epäkivi can refer to a rock that has undergone significant alteration, changing its original mineralogy and texture to the point where it no longer fits its initial description.

The concept of epäkivi highlights the importance of detailed analysis in geological studies. It underscores that visual inspection alone can be insufficient, and rigorous testing, such as chemical analysis, spectroscopy, or microscopic examination, is often necessary for accurate identification and classification. While not a formal scientific classification itself, epäkivi serves as a useful descriptive term in practical geological work, particularly during field investigations or preliminary assessments.