Blocks of green "glass" on old wreck site ... any idea?

[Jerome Smeets]

Hello,

In Southern Crete, there is an old wreck site including a few green "glass" blocks as shown on the pictures.

Not sure this is glass. It can cut your skin like glass and light goes trough it.
Also on the site, many amphori broken in tiny pieces and some kind of structure covered with grey stuff, not sure wether it's part of the boat or anchor or ?

Are those blocks common in old wreck in Greece and does anyone knows what it is exactly ?
(no reply yet from the ministry of culture)




Thanks in advance for any information