SMITHSON, SMITHSONITE, AND THE SMITHSONIAN

ROCK SCIENCE

- STEVE VOYNICK

Smithsonite, or zinc carbonate, is a favorite among mineral collectors for its range of pleasing colors and often well-developed, botryoidal form. Most collectors agree that smithsonite’s most striking color is the saturated, robin’s-egg blue of the lustrous, translucent specimens from Magdalena, New Mexico.

Smithsonite is also interesting for its unusual historical connection, which is rooted in “calamine,” a mineral that scientists initially believed to be zinc oxide. But in 1803, English chemist James Smithson demonstrated that calamine was actually a mix of three zinc minerals—an oxide, a carbonate, and a silicate. Smithson’s success in chemically differentiating oxide and carbonate minerals was a major advancement in qualitative mineralogy. In 1832, calamine’s zinc-carbonate component was formally named “smithsonite” in his honor. But Smithson’s legacy was destined to go much further.

James Smithson was born in France in 1765 as James Lewis Macie, the illegitimate and unacknowledged son of British subject Hugh Smithson, the first Duke of Northumberland. Smithson eventually adopted his father’s name, became a naturalized British citizen, and in 1786 earned a degree in chemistry from Pembroke College (University of Oxford).