How is a Secondary Deposit defined?

• A. A deposit where gems are found away from their primary source.
• B. A deposit where gems are found in the rock that carried them to the surface.
• C. A management term for shipping parcels.
• D. A method of X-ray detection.

Answer: (A)

In gemology, a secondary deposit refers to a placer-type concentration where gems have been weathered and eroded from their original rock and transported to a new location, where they accumulate away from the primary source. This means you find the gems in a location different from the rock in which they formed. For diamonds and other gem materials, secondary deposits commonly occur in riverbeds or coastal sands where water movement concentrates the heavy crystals, forming alluvial placer deposits. The other descriptions describe either the rock that carried material during transport, a non-deposit term, or a detection method, none of which define a secondary deposit.