Μαγνησία

The confusion began with Pliny the Elder. In his Naturalis Historia, written around 77 CE, he described two minerals from the Magnesia district in Thessaly: one that attracted iron (what we call magnetite) and one that did not but looked similar (what we call pyrolusite, manganese dioxide). Medieval alchemists inherited the confusion and compounded it. They called the non-magnetic mineral magnesia nigra — black magnesia — to distinguish it from magnesia alba, the white powder that would later yield magnesium. Two minerals, one place name, no clarity.

Glassmakers had known for centuries that magnesia nigra could remove the green tint from glass caused by iron impurities. They called it glassmakers' soap. In 1774, Johan Gottlieb Gahn in Stockholm heated pyrolusite with charcoal and isolated a new metal. Carl Wilhelm Scheele, who had already characterized the mineral chemically, confirmed the discovery. The new element needed a name, and the Magnesia tangle continued: it became manganese, from the Italian manganese, a corruption of the Latin magnesia.

The separation of manganese from magnesium in the scientific literature took decades. Both names derive from the same Greek place name. Both elements were identified in the same era. Both were confused with other substances for centuries. The International Union of Pure and Applied Chemistry eventually standardized the names, but the etymological kinship is permanent — two elements forever sharing an address.

Manganese found its industrial purpose in 1882 when Robert Hadfield in Sheffield discovered that adding about 13 percent manganese to steel produced an alloy extraordinarily resistant to abrasion and impact. Hadfield steel became essential for railway points, rock crushers, and prison bars. Today, about 90 percent of all manganese produced goes into steelmaking. The element that glassmakers used to remove color from glass now hardens the steel in bridges and buildings.