Sieber Agate 4mm Round AA Grade - 15-16 Inch Size_10-13x14-19mm thought to be derived from

thought to be derived from trace amounts of titanium

Phosphosiderite is a combination of phosphorus and iron

No two are exactly alike

often occurring with inclusions of white

Sieber Agate 4mm Round AA Grade - 15-16 Inch Size_10-13x14-19mm thought to be derived fromSieber agate is not a true agate but rather a glassy, dark blue grey or green copper slag that formed during ancient copper smelting in Germany, specifically from the Siebertal area. This historical "ancient slag" has a naturally swirling, intricate appearance resembling agate due to silica and mineral inclusions from the smelting process. It is a rare and collectible material known for its lapidary qualities, similar to obsidian, and is sometimes