Siltstone can be difficult to identify in the field without close examination. Weathered surfaces often appear to show sedimentary structures where none are present. Different layers weather at different rates. Siltstone is often interbedded with other lithologies.

Identification requires breaking off a small piece and observing the grain size. Scraping the surface with a nail or knife blade will dislodge tiny silt grains instead of dislodging sand grains or producing a white effervescent powder.