Skip to page content
This is a photo of a stone/rock my son found in Israel in an area that has been volcnic in the past. The surface is shiny as if it had been affected by high temperatures.
Please let me know what you think it is. The reverse is is like a normal stone.
I think this is a piece of red chalcedony, of the kind called carnelian
The surface is 'shiny' reflecting its glass-like structure, which also accounts for the conchoidal (shell-like) chipping marks.
Carnelian is formed by precipitation of the silica in cavities, and in your case it is entirely possible that it was a cavity in lava (what would have been a gas bubble when it was molten).