The southern end has deposits of rare blue clay.

Blue Mountain's name comes from the unusually blue clay that can be found around the mountain.

Well, now, in the whole world I've only had to do with one place that was a volcanic vent of blue clay.

You need some sort of blue clay for diamonds.

Yellow, blue or white clay can be used, but dark red creates the deepest gold shade.

Casting about, she found a deposit of blue clay.

Her designs are most often found pottery of blue clay or stoneware.

They used to find diamonds in blue clay which was as hard as rock.

Here, blue clay goes out from the land to under the waves.

It is thought to be named after the Aboriginal word for blue clay.