petrographically

Petrographically, the rocks are homogeneous, light to dark grey and medium- to coarse-grained.

Taken collectively, they exhibit a considerable variety of types and are of great interest petrographically.

The most common is a somewhat inflated grey grain petrographically similar to the grey pumice grains.

Deposits can be classified by their depositional environment (or otherwise by vegetation or petrographically).

Their solid products are similar but can be distinguished from one another petrographically, due to their differing crystal sizes, shapes and reflectivity.

Nile silt is readily identified petrographically, should macroscopic visual examination leave any doubt as to origin or identity.

The petrographically analysed samples point to two production areas: the Central Jordan Valley and southern Lebanon.

The western border of the mountain range is, petrographically, less clear because here its transition to the Innsbruck quartz phyllites is not clear-cut.

He also sampled a jet-black chert layer which, when observed petrographically, revealed some lifelike small spheres, rods and filaments less than 10 micrometres in size.

Various sedimentary formations underlying Puget Sound and the eastern Olympic Peninsula (such as the Crescent Formation) are of similar age, but petrographically distinct, and appear to have different sources.