To describe a rock's texture, geologists determine

the size, shape and orientation of mineral grains

Explanation:

To describe a rock's texture, geologists determine the size, shape and orientation of mineral grains.

Texture deals with the relationship between minerals within a fine mass.

Rocks are aggregate of minerals and they are fundamental building blocks of rocks. We can observe rock textures by merely looking at it with our naked eyes. Also, we can obtain thin slices and sections of rock to have a closer look into the rock.

The teacher is mostly talking about the distillation of a mixture

It shows that the experiment is designed properly.