These are brown, green and white. They all have similar lines and curved bodies somewhat. I have seen raw epidote or peridot I believe online that had similar structures but it may be common in different minerals that I am unaware of.
These were picked up on a sandy beach where the land is eroding. I am not sure if this environment can help in identifying. Most of these were covered with a thin layer of dark grey clay. I initially noticed them for the shape, I didn’t realize they were glass like until I cleaned them.
Shandy, where are you finding these? Or shall I ask, what part of the world is your beach, in the North East, Norh West? In a way it looks like slag on first look but slag does not normally come in clear. Hmmm you have me stumped at the moment. I know I’ve seen this before but I’m have a gasuius brain at the moment. It has been a long long time. I just can not place it for the life of me! So at some horrible hour of the night it will wake me or hit me when I least expect it. 
I hope it hits me soon!
Otter