Key Concepts

This exhibition examines the science and cultural influence of civilization's most sought-after mineral. Gold specimens and artifacts reveal its properties, origins, and role as a driver of human settlement and a symbol of status. Because this natural resource is unique, rare, and found globally, societies go to great lengths to acquire it.

Gold Is a Mineral, an Element, and a Metal
Gold can be defined several ways. It is a mineral—a natural solid with a crystal structure. Gold has a place on the periodic table as an element—a substance composed of a single type of atom. It is also a metal, one of a group of elements with characteristic properties. Metals tend to have a shiny luster, conduct electricity well, and can be malleable and ductile.

Gold's Combination of Physical and Chemical Properties Is Unique
Gold's attributes make it alluring, durable, and useful.

Cuff links
(England; c. 1885)
(click to enlarge) ©AMNH/Craig Chesek

Color—Yellow: Gold is the only metal that is yellow in its pure, or native, state. In nature, gold can combine with other metals, which alters its hue.

Luster—Metallic: Gold gleams because of the way it reflects light. Only silver and copper have comparable degrees of reflectivity.

Reactivity—Nearly inert: Although gold alloys, or mixes, with metals easily, it reacts chemically with very few nonmetallic substances. Therefore, it resists tarnish and corrosion—forms of deterioration from gases or liquids.

Conductivity—Excellent: While copper and silver conduct heat and electricity better, gold's nonreactive nature leaves it more conductive for longer.

Density—High: Gold weighs 19.32 grams per cubic centimeter. That's nearly twice as hefty as lead.

Hardness—Very soft: On the 10-tier Mohs hardness scale for minerals, gold is a 2—very soft. It is easy to manipulate.

Malleability and Ductility—Readily deformed: A malleable metal can be hammered into sheets, and a ductile metal can be easily drawn into wire. Gold is superlative at both.

Minerals Form by Geologic Processes
Over millions of years, processes such as magmatism, erosion, and sedimentation work together to form and deposit minerals in Earth's crust. Gold deposits can be dispersed microscopically in rock, or concentrated in veins and placers. Veins form when minerals dissolved in hydrothermal fluids rise through fractures in rocks deep in the crust and crystallize out of solution. Eventually, wind and surface waters erode gold grains away from veins. Placer deposits form when grains collect in lake-, river-, and seabeds.

Natural Resources Are Valuable to Civilizations
Gold is found worldwide, but it is rare—it comprises just five out of every billion atoms in Earth's crust. Its rarity and distribution have driven societies all over the world to seek and cherish gold since its first known use about 6,000 years ago. As the population increases, so does the demand for gold.

Using gold: Gold's most common use is for adornment. It is also used for religious objects, tableware, awards, commerce, electronics, and medical applications.

Seeking gold: History reveals that where gold was found, human settlement often followed. After the late 15th century, gold owned by South and Central American cultures drew plundering European explorers and colonists. Gold deposits have set in motion prospectors and prosperity in many locales.

Valuing gold: People use gold to signify social status. Archaeologists find gold artifacts from societies stratified by wealth or power, such as the ancient Egyptians and the Inca. Less stratified societies typically do not value gold as highly.

Acquiring Natural Resources Affects the Environment
Gold mining employs massive amounts of rock and hazardous chemicals; it deforms and can pollute landscapes. Since the largest, most accessible gold deposits in Western countries have long been tapped, gold mining companies today often operate in developing countries, which can have weak environmental and human rights protections. As gold's environmental and social tolls become more apparent, communities, workers, companies, and consumers are weighing gold's costs against its value.