spiegel iron

from the GNU version of the Collaborative International Dictionary of English.

• (Metal.) A fusible white cast iron containing a large amount of carbon (from three and a half to six per cent) and some manganese. When the manganese reaches twenty-five per cent and upwards it has a granular structure, and constitutes the alloy ferro manganese, largely used in the manufacture of Bessemer steel. Called also specular pig iron, spiegel, and spiegeleisen.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun spiegeleisen

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun pig iron containing manganese; used as a deoxidizing agent and to raise the manganese content in making steel