Glintshore

Described as an "Isle of Glass" by Kamaljiori
The captain of the airship that Vox Machina chartered in Ank'harel described the Glintshore as a "barren wasteland".
Located in the island chain near where J'Mon Sa Ord indicated Thordak "died" 400 years ago.
The glass that covers the beach seems volcanic, and there is a small mountain on the island that, imo, was very implied to be a volcano.
Inside the "mountain", Vox Machina found a small altar that had a compartment containing a "Gate" spell scroll. There was a tunnel that lead deeper in to the mountain that Vox Machina did not investigate.
Doctor Anna Ripley was planning some manner of ritual on this island, but Vox Machina interrupted it before she could complete it.

Type

Island