The Big Hole: The other beauty in kimberlites and a wealth of information.

To the untrained eye, even freshly broken kimberlite looks like just another boring pile of grey rocks.

This is far from the case... true the matrix is pretty ordinary... but its what's in the matrix that is the interesting stuff.

Looking closer one can see that there are many different foreign bodies included within the rocks.

It's these foreign bodies that render kimberlite of such scientific interest. Not only are the diamonds occasionally encountered here but many other rocks and minerals from deep down in the earth.

Some of these foreign bodies are large chunks and even boulders of unaltered mantel material.

The drab light brown rounded bolder (3 in picture below)starts too look a little more appealing once one is polished (for the plaque in this case).

Adding a little water brings out the colors better and we see that the rather ordinary looking rock is actually a large massive cluster of crystals.

Zooming up close we see that it consists of many different colored crystals from light green to dark green, white, orange, brown and even purple.

This rock is called a peridotite (after the predominant green crystals) and is is one of the main rocks from 100's of km below the surface, in the Diamond Stability Zone.

IMG Source

Kimberlites are not only subterranean transport mechanisms they are also time capsules.

Studying the various kimberlite pipes that have erupted at different times during the long life span of the earth we have snapshots of what was going on deep down below during those geological ages.

There is still plenty to be learned from these rocks, considering the first of them were only discovered, identified and described a little over a century ago.

Other posts in this series:

The Big Hole. What is the big hole and where is it?
The Big Hole: Part of a greater whole
The Big Hole: Kimberlites, how do they form.
The Big Hole: Diamonds are a girls best friend...