|Diamond- Round Brilliant Cut|
|Different views of a Round Brilliant Cut|
|Diamond in the Ore|
If the diamonds are found in and around the pipes then this kind of deposits are called primary deposits. And all other deposits are called secondary deposits. If due to weathering conditions, diamonds were carried into neighboring rivers and streams, and even into the ocean. Since diamonds are heavy, they sink to the bottom when caught in small whirlpools. Deposits in rivers and streams are called alluvial deposits and often contain higher quality diamonds than primary deposits within a diamond pipe because the better ones are more likely to survive the water's tumbling action against rocks. If the diamonds reach the ocean, they are called marine deposits.
Renée Newman, Diamond Handbook- a practical guide to diamond evaluation: completely revised 2nd edition