The very hard dense rock is used as a whetstone.

Must be dense rock around... signal is getting weaker and I have a job holding control.

You know our minds cannot penetrate dense rock deeply enough to strengthen the crust.

Bituminous coal is a dense rock, black but sometimes dark brown.

They are hard, dense purple-black rocks with considerable content of pyrite.

The heads were sculpted out of a hard, dense rock called basalt.

What forces had sliced this razor-thin cleft in the dense rock around them?

Second, being an unusually dense rock, eclogite can play an important role in driving convection within the solid Earth.

How does this oil move through the dense rock and into wells that take it to the surface?

The result is a cylinder of hard, dense, black synthetic rock.