Description
Sieber Agate is actually not an agate but a glassy copper slag. These copper slags were formed during the extraction of copper from copper ore by means of high heating. The fact that the material has been melted is still clearly visible. The material is glassy, sometimes with a blue tint. Found in Siebertal, Harz, Germany. The color is a beautiful blue and it is rare.
Sieber agate is a very unique lapidary material from Germany, displaying a subtle play of swirling patterns of dark electric blue. Although it is sold as 'agate', it is technically a glassy slag from an ancient copper smelting process more than 1,400 years old. It characteristically contains numerous nail-width vesicles and behaves much the same as obsidian.
