You can’t find glass itself, but you can craft it by getting two quartz.
(which can be found in many places, especially the safe shallows)
Quartz+Quartz=Glass
Just get yourself some crystals thingies sittin around in caves.
2x quartz makes 1 glass. You can’t find that material by itself.
You need quartz, which is found in the red grass area with sand-sharks just past the kelp forest, you'll need 2 quartz to make it and i highly recommend you take a prawn suit or sea-moth there, if you have one
What do you think?