It's impossible to say definitively which mineral is *not* a natural resource of the West without knowing which specific region you're referring to. "The West" is a broad term that can encompass many different areas of the world.

Here's why it's difficult to answer:

* "The West" is geographically ambiguous: It could refer to the American West, Western Europe, Western Asia, or other regions.

* Natural resource distribution varies: Different geological formations and regions have different mineral deposits.

* New discoveries are constantly being made: What was once considered scarce may become abundant with new exploration techniques.

To answer your question, you would need to specify a particular region or country.

For example, if you're asking about the American West:

* Diamonds are not a natural resource: While diamonds are found in other parts of the world, they are not a major resource in the American West.

Once you specify the region, I can give you a more accurate answer.