What defines an eluvial deposit?

An eluvial deposit is characterized by gemstones that have been eroded from their source rocks but have not been transported far from that original location. This process typically occurs due to natural weathering and erosion, which releases the gems but leaves them relatively close to where they formed. In eluvial deposits, the gemstones can often be found in situ, meaning they are still embedded within the soil or sediment of their original environment, rather than being moved to a new location by water or other geological processes.

In contrast, deposits related to oceans would not fit the definition of eluvial, as they are more associated with marine environments rather than terrestrial erosion. Artificially created gemstones do not qualify as eluvial deposits, since they are not naturally occurring materials. Volcanically formed deposits usually refer to deposits created from the activity of volcanoes rather than the gradual erosion processes that define eluvial deposits. Thus, the correct definition emphasizes the closeness of the gemstones to their source, which is a hallmark of eluvial deposits.