Chalcedony / hydrochloric acid Hvalfjörður, Iceland Example ...
Description: Chalcedony / hydrochloric acid Hvalfjörður, Iceland Example of the results on a different kind of "junk" piece - a piece that's dark, dull, dirt-colored, not as glassy... basically inferior chalcedony. After acid treatment, note how light it is. It's also become a bit porous as the contaminant material was eaten away.