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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