A naturally occurring substance in the solid inorganic crystalline state is known as a mineral.

Here's why:

* Naturally occurring: This means it's found in nature, not created by humans.

* Solid: It has a definite shape and volume.

* Inorganic: It is not derived from living organisms.

* Crystalline: It has a specific, repeating, three-dimensional atomic structure.

Examples of minerals include: quartz, diamond, gold, and salt.