Agates or glass?

[Chengjing]

Found a few almost clear pieces on the beach. Can you guys tell what they are? Thanks!

 

[CoinFetcher]

The last two (last 4 pics) are agate - others are glass

 

[Chengjing]

Thanks for the advise!

 

[Chengjing]

I was trying to drill a hole in the first piece, sadly I cracked it. The cracked surface is totally transparent, almost feel like resin, it is sharp but not quite like glass, I am not sure if it is glass, can someone have a look and let me know



Thanks

Jing