The Minerals That Made America

Iron, Copper, Lead & Zinc Transformed the United States Into a Major Industrial Power

- STEVE VOYNICK

Fluorite on sphalerite from Minerva No. 1 Mine in Illinois. Ex. Walt Gaylord Arkenstone, iRocks.​com

Distinctive crystal forms and colors, availability and affordability make specimens of hematite, magnetite, native copper, chalcopyrite, chalcocite, galena and sphalerite popular with many mineral collectors. Along with collectibility, these seven minerals share a historical significance: They all played major roles in the transformation of the United States from a collection of former colonies into an industrial power.

These minerals were the primary sources of iron, copper, lead, and zinc - the metals that built the infrastructure for public works, transportation, manufacturing and defense. During the nation-building era from the mid-1800s to the early 1900s, access to large deposits of these seven minerals was critical to industrial growth.

During its first 60 years of independence, the United States imported most of its metals. The development of the first substantial domestic sources of metals in the 1850s was a turning point in the nation's history. The ready availability of iron and copper opened the door to rapid industrial growth and provided exportable commodities to alleviate a negative balance in foreign trade.

HEMATITE & MAGNETITE

The minerals that had the greatest impact on national growth were hematite and magnetite, the iron oxides that are the primary ores of iron. Hematite (Fe2O3), the most abundant and widely distributed iron mineral, consists of 69.94 percent iron, crystallizes in the trigonal system, and has a high specific gravity of 5.3.