White Sands in New Mexico is the largest surface deposit of gypsum on Earth.

While ordinary sand is made of silica, the dunes of White Sands consist of gypsum, chemically known as calcium sulfate.


Gypsum is a relatively common material. Human beings have used gypsum for thousands of years. The ancient Egyptians plastered the vaults of their pyramids with it. The ancient Greeks made windows out of transparent gypsum crystals known as selenite.

Gypsum is a component of plaster.

Formation of White Sands

Around 100 million years ago, shallow seas that covered much of the southwestern United States started to retreat. They left behind lakes of saltwater that slowly evaporated in the sun.
Gypsum, along with ordinary salt, precipitated from the mineral-rich solution and formed thick layers on the old seabed.

About 65 million years ago, the San Andres and Sacramento Mountains were created (at the same time as the Rocky Mountains) by upheavals in the Earth's crust. This exposed more beds of gypsum to the elements.

Rain and melted water from the mountains dissolved the gypsum and washed a concentrated solution of the mineral to a lake, known as Lake Lucero.

This lake, which lies at the foot of the San Andres Mountains, has a deep basin, but no outlet. It is the source of the White Sands.

Water draining into the lake is trapped and is evaporated by the combined effects of warm temperatures and steady winds. This causes a crust of glassy selenite crystals is formed on the lake's surface.

Prevailing southwesterly winds convert the delicate sheets of selenite into tiny gypsum grains and deposit them farther up the Tularosa Basin to the northeast of the lake

The loose grains, which turn to powder when rubbed between the fingers, are piled up to form dunes often as high as 15m (50ft) above the desert floor.

The dunes of White Sands do not remain still. The wind moves them up to 10m (33ft) per year.

Life on White Sands


Many different types of plants are able to find a secure footing on the constantly shifting gypsum dunes.

The yucca, sumac and cottonwood manage to survive in the alkaline sands and the almost continuous dryness.

To cope with the movement of the dunes, the roots of some of these plants, especially those of the cottonwood, may reach over 30m (100ft) long.

Our Lord's Candle, a form of yucca, was named for its waxy, bell-like flowers, which resemble flaming tapers.

Symbiotic Relationship

The yucca can only be pollinated by the yucca moth, and the yucca moth will only lay its eggs in the yucca's flowers.

When the flowers open, the moth collects the pollen and rolls it into a ball with its leg. The moth then finds another flower. It places the pollen ball on the stigma, thus fertilizing the flower, and lays between one and four eggs at the flower's base.

The moth's eggs and the yucca's seed develop together. When the larva hatches, it eats about half of the ripened seeds. After a few days, it munches its way out of the yucca, drops to the round and burrows into the loose gypsum where it pupates.

After a year, the adult moth emerges.


Only a few animals make White Sands their permanent home. They include the bleached earless lizard, and the nocturnal white Apache pocket mouse. These animals cannot be found anywhere else on Earth.

Horned lizards of White Sands can change their color to match their surroundings. On the usual brown deserts of New Mexico, they are patterned with shades of brown. On the basalt lava flows that dot the region, there are black horned lizards. The horned lizards that live on the surface of White Sands are pure white.

Many more animals and plants can be found at the margins of White Sands.

Coyotes, gophers, badgers, kangaroo rats, porcupine and snakes can be seen.

The buffalo gourd, with gold, foul-smelling flowers, grows alongside purple sand verbenas and pink centauriums.