The famous Thuringian Forest Glass - for 200 years a highly valued glass specialty and today as an object of collectors' passions often imitated cheaply - owes its green gradient shimmer to the high proportion of iron oxides in the sands of the Thuringian Forest. In addition to the natural green tones, the so-called "Gispen", air bubbles trapped in the glass, are characteristic of the traditional processing method. No two glasses are the same. This is genuine Thuringian Forest glass from the area around Ilmenau and Stützerbach.

In the Farbglashütte Lauscha in the south of the Thuringian Forest, the archetype of Thuringian glass is blown. Sand, potash and lime are used to melt the raw material for those glasses that became known and loved as forest glasses because of their light green hue. As early as 1700, forest glass was used for equipment in chemistry and pharmacy, and later it was sold as household glass. The green shimmer of forest glass - today often imitated by mainly Spanish colored recycled glass - is caused by iron silicates and the residues of charcoal. The typical small bubbles (gispen) are a sign of authenticity and the old traditional way of processing. The glass is mouth-blown in a beech wood mold.