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Name: Coby
Status: student
Grade: 6-8
Location: PA
Country: USA
Date: N/A 


Question:
In kimberlite, (the rock in which diamonds are found),does it first contain coal which then turns into diamonds?



Replies:
Coby,

Although diamonds and coal have carbon, they form under entirely different geologic conditions. Diamonds form through cooling of high-pressure carbon-rich fluids that find their way to Earth's surface via natural pipes (well pipe-shaped fractures in Earth). Their type locality is in Kimberly, South Africa, and therefore we say that diamonds form in Kimberlite pipes. It is almost pure carbon.

Coal, on the other hand, forms from the anaerobic decay of plant material that is buried at minimal depths. Coal has carbon and many other elements in its make-up. We do not squeeze coal to get diamond.

Did you know that diamond is not the hardest naturally occurring mineral? The rare mineral lonsdaleite is 58% harder than diamond and may form when meteorites containing graphite (not coal) hit Earth.

Les

---
Leslie Kanat, Ph.D.
Professor of Geology
Department of Environmental Sciences
Johnson State College



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