Large Sieber agate chunk (800g!)
Although called “Agate”, Sieber Agate is formed when copper is being extracted from copper ore and is not actually an Agate at all.The copper smelting process is over 1400 years old, leaving this glassy material that is very deep blue, with several shades of blue swirling in together.Sieber Agate is found in Siebertal, Harz, Germany. It has very similar characteristics to Obsidian. It is a piece of man's history, estimated to be between 600-1400 years old and is NOT contemporary copper smelting slag.This is a fairly rare stone and would be a wonderful addition to any crystal collection. Measures approximately 4 x 3 x 3 and weighs 800g (over 1lb 12oz). It is a much larger, heavier piece than most other pieces I have seen listed other places.