Sandstone: A Common Sedimentary Rock

What are the characteristics of sandstone?

Sandstone contains quartz and feldspar. It is often tan, brown, yellow and/or red. It may have a hardness of about 6.5. Can sandstone be described by a chemical formula?

A. Sandstone is a mineral because minerals always have a hardness of 6.5.
B. Sandstone is a mineral because minerals are always made of quartz.
C. Sandstone is not a mineral because each mineral can only come in one color.
D. Sandstone is not a mineral because minerals are pure substances.

Answer: D

Sandstone is not a mineral because minerals are pure substances.

Sandstone is a common sedimentary rock that is composed of quartz and feldspar. It typically comes in various colors such as tan, brown, yellow, and red. The hardness of sandstone is usually around 6.5 on the Mohs scale.

While sandstone contains minerals like quartz and feldspar, it cannot be described by a chemical formula because sandstone is not a pure substance. It is a rock made up of various components, not a single mineral with a fixed chemical composition.

Minerals, on the other hand, are naturally occurring inorganic substances with a definite chemical composition and crystal structure. They are pure substances, unlike sandstone which is a rock formed from the consolidation of sedimentary grains.

Therefore, sandstone is not considered a mineral because it does not meet the criteria of being a pure substance like minerals.