Taxonomy term

Gold was highly valued by early civilizations for its scarcity, durability and characteristic color, reminiscent of the sun, which was worshiped by some as a deity. It was first recovered from streambed gravels (placers), where it occurred in native form, and thus did not require extraction from ores. It was both essentially indestructible and easily worked. Gold nuggets were prized possessions that could be fashioned into bars of different standard weights and into ornaments and items of adornment that also served as portable wealth. Gold leaf (gold beaten into thin sheets) has been used to decorate significant architectural structures since ancient times. In the 7th century B.C., the Etruscans used gold to make false teeth, and it is still used in dentistry today due to its nontoxicity, durability and beauty.

Over the last year and a half, the Western U.S. has suffered a rash of devastating landslides. The streak began in September 2013, when heavy rains triggered widespread debris flows across the Colorado Front Range. Then came the tragic landslide that buried Oso, Wash., killing 43 people. Two months later, the West Salt Creek slide, a behemoth rock avalanche in western Colorado, killed three people as it barreled down a 5-kilometer-long path.

Antimony is a lustrous silvery-white semimetal or metalloid. Archaeological and historical studies indicate that antimony and its mineral sulfides have been used by humans for at least six millennia. The alchemist Basil Valentine is sometimes credited with “discovering” the element; he described the extraction of metallic antimony from stibnite in his treatise “The Triumphal Chariot of Antimony,” published sometime between 1350 and 1600. In the early 18th century, Jöns Jakob Berzelius chose the periodic symbol for antimony (Sb) based on stibium, which is the Latin name for stibnite.