Why mineral chalcopyrite and sphalerite hard to find in alluvium placer deposit?

Chalcopyrite and sphalerite are minerals that are not commonly found in alluvium placer deposits. This is because they are heavy minerals that are dense and resistant to weathering 1. As a result, they tend to remain in the primary source rock where they were formed, rather than being transported by water and deposited in alluvium placer deposits.

chalcopyrite and sphalerite are heavy minerals that are dense and resistant to weathering. As a result, they tend to remain in the primary source rock where they were formed, rather than being transported by water and deposited in alluvium placer deposits.

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