1) Everyday German physics term 2) Familiar German physics term 3) German physics term 4) Pig iron 5) Pig iron containing manganese 6) Prevalent German physics term 7) Spiegel 8) Spiegel iron Found on https://www.crosswordclues.com/clue/spiegeleisen
Spiegeleisen (literally `mirror-iron`, Spiegel—mirror or specular; Eisen—iron) is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Historically, this was the standard form in which manganese was traded and used in steel making. Being remarkably free from impurities, such as phosphorus,..... Found on http://en.wikipedia.org/wiki/Spiegeleisen