WHY SO "DIRTY"

"Dirty diamonds" are crystals that grow in the salt flats surrounding the Great Salt Lake. Though their nickname refers to them as diamonds, they are made of gypsum, a mineral often found in salt flats. The crystals are filled with “impurities” and inclusions, making them rough or cloudy, hence the “dirty” part of their nickname.
These crystals often grow in oolitic sand, a grainy substrate formed by layers of minerals around a core particle. This provides a textured matrix for crystal development that can lend to their irregular structures and textures. The intense sunlight can expose the crystals to the weather, helping to lend to their rough, dirty appearance, often marked by inclusions or cloudiness.

The Crystals

WHY SO “DIRTY?”

"Dirty diamonds" are crystals that grow in the salt flats surrounding the Great Salt Lake. Though their nickname refers to them as diamonds, they are made of gypsum, a mineral often found in salt flats. The crystals are filled with “impurities” and inclusions, making them rough or cloudy, hence the “dirty” part of their nickname.
These crystals often grow in oolitic sand, a grainy substrate formed by layers of minerals around a core particle. This provides a textured matrix for crystal development that can lend to their irregular structures and textures. The harsh sunlight can expose the crystals to the weather, intensifying their rough, dirty appearance, often marked by inclusions or cloudiness.

HOW THEY FORM

Extreme fluctuations in temperature and humidity cause water to evaporate from brine (saltwater) pools in the salt flats. The brine leaves behind dissolved minerals like gypsum, which crystallize over time. Gypsum is composed of calcium sulfate and water and forms because it is less water soluble than other salts. As water evaporates, the gypsum crystallizes out of the liquid that is left. While the gypsum develops, the sandy, salty surface forms a hard crust of salts that protects and seals it from further evaporation. The crust is often very fragile and can easily break apart.

THE LIFE OF THE CRYSTALS

Pressure from underlying water, tectonic movements, or shifts in the water table can push the trapped crystals upward, creating crystal mounds on the surface. After reaching the salt-encrusted surface, their chances of remaining whole drastically decrease. The crystals can grow into many shapes, ranging from clear and shiny to dark, cloudy, and rough. They can become large but snap with little force, making it challenging to find whole, large pieces. Often, they fracture into many slices held within their salt crust mounds, creating a windowpane effect with crystal slides fanned out and glued together by the salty and sandy surface.
The salt flats constantly change due to inconsistent weather conditions, evaporation rates, and geological activity. The process is unpredictable, and new crystals continually form, rising to the surface and becoming exposed as older crystals break down, becoming one with the sandy shores again.

THE LIFE INSIDE THE CRYSTALS

During crystallization, halophilic (salt-loving) microorganisms can become trapped inside the growing crystals. These extremophiles (microbes that survive in extreme environments) may remain preserved within the crystals for long periods. Researchers have found viable halophilic archaea inside fluid inclusions in gypsum crystals from salt-rich environments, including the Great Salt Lake. These findings suggest that dirty diamonds can preserve geological information and act as natural time capsules for microbial life.

This makes gypsum crystals valuable as they offer insights into Earth's ancient ecosystems and the possibility of life in extraterrestrial salt-rich environments, like those on Mars.

The lake

satellite images comparing GSL 1980's (left) vs 2020s (right)

GSL 1980's (left) vs 2020s (right)

The Great Salt Lake is a very salty, large, and shallow lake in Utah. Its salinity can reach nearly eight times that of the ocean in some areas. The lake's surface area is highly variable—typically around 1,700 square miles (4,400 km²), but it has dropped to a historic low of roughly 950 square miles due to drought and water diversion. Because the lake is shallow, with depths ranging from 13 to 33 feet, its surface area changes drastically with seasonal precipitation and evaporation. These figures are often estimated by satellite and are constantly in flux.
The Great Salt Lake is a terminal lake, meaning it has no natural outlet. It is the remnant of ancient Lake Bonneville, a massive Ice Age pluvial lake fed by rainfall. Today, it receives water primarily from the Bear, Jordan, and Weber rivers. Since water escapes only through evaporation, salts and minerals accumulate over time. This high salinity limits aquatic life but supports brine shrimp and salt-tolerant microbes. The lake's density even allows people to float with ease.

salt encrusted shores leading to The Great Salt Lake

Despite its harsh conditions, the lake is a crucial ecosystem. Its wetlands serve as vital habitats for millions of migratory birds, including Wilson’s phalaropes, American avocets, and eared grebes. These birds rely on the lake for food and rest during migration. Brine flies and brine shrimp, which thrive in the hypersaline water, are key food sources.
The lake is under significant threat due to water diversion for agriculture, urban development, and industry. This reduction in inflow, coupled with climate change, has led to record-low water levels. As the lake recedes, it exposes large areas of dry lakebed.
The exposed lakebed contains fine sediment rich in toxic substances such as arsenic, mercury, and pesticides. During windstorms, this dust becomes airborne, posing serious health risks including respiratory illnesses, cardiovascular problems, and even cancer. Communities around the lake have reported increased rates of asthma and bronchitis.

overlooking The Great Salt lake from The Spiral Jetty

Lower water levels reduce wetland habitat and threaten the survival of the lake’s unique wildlife. If salinity rises too high, brine shrimp populations could collapse, disrupting the entire food chain. This would also hurt the brine shrimp harvesting industry, which supports aquaculture and other markets.
As the volume of water decreases, pollutants become more concentrated. Agricultural runoff, heavy metals, and other contaminants alter the lake's chemical composition, endangering aquatic life and destabilizing the ecosystem.
The lake helps regulate the local climate by moderating temperatures and influencing precipitation patterns. A smaller lake surface increases evaporation and intensifies drought conditions, creating a vicious cycle that accelerates the lake’s decline.
Solving the Great Salt Lake crisis requires coordinated action. This includes reducing water diversion, restoring river inflows, protecting wetlands, and addressing broader issues like climate change. Without intervention, the region could face irreversible environmental damage with lasting consequences for wildlife, public health, and the economy.

THE SOUNDS

The play button at the top of the page is a generative soundscape created by Carey Campbell that builds itself as you listen.

Constantly in flux, you will never hear the same assortment of sounds twice, honoring the environment that inspired its conception, the Great Salt Lake.