What is NOT a classification of grain or particle sizes in soil?

In soil science, grain or particle sizes are categorized based on their dimensions. Terms like boulders, fines, and sands refer to specific ranges of particle sizes:

• Boulders are the largest particles, typically greater than 256 mm in diameter.

• Fines refer to the smallest sizes, including clay and silt, which are less than 2 mm in diameter.

• Sands fall in between, referring to particles that range from 0.063 mm to 2 mm.

Granite, however, is not a classification of grain or particle size. It is actually a type of igneous rock that consists primarily of quartz, feldspar, and mica, and while it can break down into smaller particles that might fall into other size classifications, it does not itself define a size category in the context of soil particle sizes. Therefore, identifying granite as a particle size classification is incorrect, making it the right choice for the question.