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From Alluvial to Primary Deposits

In my last blog I asked you if you could guess the four types of deposits where diamonds are found.  So, do you have your answers?! Are you ready to learn if you’re right or not?!  Okay, here we go, they are (drum roll pleeeeease…)……..primary, secondary, alluvial and marine deposits!  Did you get some or all correct? Now, here is the definition of each….a gem that is found in a primary deposit, is a gem that is found in the rock that carried the stone to the earth’s surface.  Gems found in secondary deposit are gems that were somehow carried away from the primary deposit.  How could the gems be carried away you ask?  Well, natural forces like rain, wind, heat, and cold could break up the host rock and then this broken rock, containing the gems, separates from the primary source.  Gems found in alluvial deposits mean they were found in river or streams.  Gems found in marine deposits are gems that have travelled from rivers into the sea and deposited offshore.  So, now that you know the four deposits where diamonds are found, can you take a guess which deposit was the only place diamonds were originally thought to be found and which deposit is the most common place to find diamonds, today?  Next month I’ll tell you!