8 Intriguing Facts About Sand

Ah, sand. Every summer, it becomes a key ingredient in how beach-goers either bask in the fun or endure the heat. But whether you love it or despise it, you’ve probably asked yourself where sand comes from, why it sometimes looks different, or what exactly it is. Keep reading to find the answers to those questions and beyond.

1. Sand is composed of crystals. (And sometimes fish waste.)

By definition, sand is made up of tiny, loose grains of material that are larger than silt but smaller than gravel. Most of the sand found on beaches originates from eroded rock, such as sandstone, but it can also come from crushed seashells, parrotfish waste (which is tiny, undigested bits of coral skeleton), or the remains of calcium-rich sea creatures known as foraminifera.

Sand can also be made up of crystals. Quartz, the most common mineral found in sand, is abundant in Earth's crust and can withstand the weathering process better than many other minerals. Sands with high quartz content are often called silica sand, composed of a lattice of silicon dioxide (one silicon atom for every two oxygens). However, quartz isn't the only gem to be found in sand—garnet, tourmaline, topaz, and more can also make an appearance. Which means...

2. Sand appears in a stunning natural array of colors.

Many famous beaches are known for their striking white sand, but sand comes in nearly as many hues as the rocks and shells that make it up. White Sands National Park in New Mexico, for example, features 275 square miles of sand dunes almost entirely composed of pure gypsum—this is typically a desert phenomenon due to the mineral’s tendency to dissolve in water.

At the other end of the spectrum, black sand often contains high concentrations of magnetite or other iron ores, such as those found on Whatipu Beach near Auckland, New Zealand. Black sand can also be the result of volcanic activity, like on Punaluʻu Beach in Hawaii, where sea-worn basalt particles—formed when lava rapidly cooled upon entering the ocean—create the distinctive black sand.

In addition to black and white, there are pink sands, like those found on Elafonisi Beach in Crete. These sands are made up of crushed red foraminifera shells blended with otherwise white sands. Papakolea Beach’s distinctive green sand comes from the mineral olivine. In Iceland's Hverir Geothermal Area, yellow sulfur granules are left behind as moisture evaporates. The grains in Saudi Arabia's Al-Dahnā’ desert are coated with iron oxide (commonly known as rust), giving them a red hue, while Namibia’s mining operations have created blue sand from the country's abundant sodalite deposits.

3. Sand is the world’s most extracted resource.

According to the UN, the global industries consume enough sand every day to construct a wall 88.5 feet (27 meters) tall and 88.5 feet (27 meters) wide around the entire Earth. That amounts to 50 billion tons of sand daily. So where does it all come from? Mostly beaches, including ocean shorelines, lakeshores, and riverbanks. In fact, the illegal sand trade in India is causing environmental damage by mining sand from riverbeds, creating deep pits that pose a danger to bathers. Large-scale sand-mining operations have also worsened flooding and erosion problems related to climate change.

4. Sand plays a crucial role in a staggering range of everyday products.

Sand is virtually everywhere and is used for nearly everything. Take a look around—do you see anything made of glass? A window, a glass cup, the glass screen of your smartphone? The internet travels to your home through fiber optic cables, and your building is likely insulated with fiberglass. All of these items once started as silica sand, heated and processed in various ways to produce different goods. But glass is just one material made from sand.

Sand is also a key component in metal casting, water filtration, ceramic glazes, paint coatings, and even in the production of detergents and adhesives. However, the largest consumer of sand is the construction industry. Basic building materials such as mortar, stucco, and concrete all rely on sand. The ongoing global urbanization, particularly in Africa and Asia, is a major factor driving the high demand for sand mining.

5. Microscopic creatures make their homes in the sand.

Tardigrades—affectionately called “water bears” for their bear-like shape and love for aquatic environments—are minuscule creatures known as interstitial meiofauna (Greek for “lesser animals”). They represent just one of the many microscopic species that thrive within grains of sand around the world. Biologist Olav Giere estimates that 50,000 to 100,000 meiofauna could be living beneath every footprint in moist sand. These creatures feed on even smaller organisms, bacteria, and debris in their sandy habitats, essentially performing beach cleanup duties. (Check out some remarkable close-up images of meiofauna here.)

6. Arena is the Latin term for 'sand.'

This might not surprise those who speak a Romance language, such as Spanish or Italian, as the word ‘arena’ (or more precisely ‘harena’) translates to ‘sand’ in English. Due to its remarkable absorption properties, sand was once used to cover the floor during gladiatorial combat in amphitheaters across the Roman Empire. Over time, the area where these battles took place became synonymous with the term. Today, we use the word to describe a venue (similar to an amphitheater) designed for large-scale entertainment, much like the Colosseum during its glory days.

7. Buddhist monks use colored sand to convey deeper aspects of their philosophy.

In a scene from the 2011 film Samsara, a group of elder monks, faces just inches from the ground, carefully tap sand from metal cylinders, creating intricate colored patterns with each precise movement. Together, they are crafting a mandala, symbolizing universal perfection—representing symmetry, beauty, and divinity.

Studying a mandala is a form of meditation; a study of nature itself. However, in Tibetan Buddhism—the tradition that uses sand to create mandalas—a mandala signifies the sacred residence of a deity. Its creation is considered a journey toward enlightenment, as the deity is said to reside at the center.

As the mandala is formed over days to weeks (or longer), the monks and observers meditate on its divine presence. Once the design is complete, a brief moment of reflection takes place, followed by the ritual destruction of the art, symbolizing impermanence—one of Buddhism’s core teachings. The sand is gathered and released into a nearby water source, spreading blessings to the world around it.

8. Sand exists on other planets too.

It’s one thing to think about sand on Earth, even as a symbol of life's impermanence, but it’s truly astounding to realize that sand exists on other worlds as well. The Apollo moon missions returned 842 pounds of lunar rocks, pebbles, and sand, which are still being analyzed today. Meanwhile, the Curiosity rover has been exploring the famous red sands of Mars for over a decade. Even more fascinating are the sand dunes found beyond Earth.

A 2022 study in Nature Astronomy revealed that sand dunes are present throughout our solar system. Satellite imagery from Venus, Earth, Mars, Titan, Triton, and even the distant Pluto all show signs of aeolian (wind-driven) surface features. The different patterns of these dunes could offer clues about their formation and provide insight into the composition of these other worlds.

For instance, the dunes on Pluto are believed to be made of methane or nitrogen ice. However, in order to move these particles, the winds on Pluto would need to blow at extreme speeds, according to the research team. Instead, they suggest that Pluto’s dunes might actually be sublimation waves—where a solid (like frozen methane or nitrogen) bypasses the liquid phase and transforms directly into a gas due to the winds. This results in a ripple-like effect that resembles dunes, but isn’t formed by sediment erosion as typical dunes are.