Question

Obsidian and pumice are igneous rocks that contain no crystals. what does that tell you about how they formed?

Answer 1

Answer:

Obsidian is a very shiny natural volcanic glass.

Notice in the photo to the left how it fractures. Obsidian is produced when lava cools very quickly. The lava coo ls so quickly that no crystals can form. When people make glass they melt silica rocks like sand and quartz then cool it rapidly by placing it in water.

Answer 2

Obsidian is a very shiny natural volcanic glass.

Notice in the photo to the left how it fractures. Obsidian is produced when lava cools very quickly. The lava coo ls so quickly that no crystals can form. When people make glass they melt silica rocks like sand and quartz then cool it rapidly by placing it in water.

its the answer...