Question

this question has two parts. first, answer part 1. then, answer part 2.
part 1
the picture shows samples of obsidian, a type of igneous rock.
which best describes the texture of the two rocks on top?
source: u.s. geological survey
they are clastic
they have no grains
they are nonfoliated
they have slight banding

Explanation:

Obsidian is an igneous rock formed from rapidly cooled lava. When lava cools quickly, there is no time for mineral grains to form. Clastic texture is for sedimentary rocks made of fragments. Non - foliated and slight banding are terms more related to metamorphic rocks.

Answer:

They have no grains.