what is the main idea of this passage?
a
clear glass that you can see through is called
translucent
and b
ed through
obsidian is a type of opaque glass often formed
around volcanoes.
glass also forms naturally when tava bursts from a
volcano and then cools.
the world cute de
the d e the
glass most of us
don't give much
glass is an amazing substance that can be formed
naturally or manufactured