Gary Arndt (0:00)

One of the most common substances on Earth is sand. Most people don't think a whole lot about sand, but sand is an extremely important part of our world. It isn't just for building sandcastles and going to the beach. Sand is the second most consumed resource in the world after water. There is an entire science to sand what different types consist of, how it's made, and even how it moves. Learn more about sand and the surprising complexity of a seemingly simple subject on this episode of Everything Everywhere Daily. This episode is sponsored by Masterclass. If you're listening to this podcast, then you are someone who is curious about the world and loves to learn. And if you want to give the gift of learning and knowledge this Christmas, you can't do better than Masterclass. Masterclass offers online classes from some of the most successful instructors in the world. In their fields. You can learn cooking from Gordon Ramsey, conservation from Dr. Jane Goodall, disruptive entrepreneurship from Sir Richard Branson, mathematical thinking from Fields Medal winner Terence Tao, and diplomacy from former Secretaries of State Madeleine Albright and Condoleezza Rice. You can access over 200 classes across 11 different categories. Masterclass always has great offers during the holidays, sometimes up to as much as 50% off. Head over to masterclass.com everywhere for the current offer. That's up to 50% off@masterclass.com everywhere. Once again, that's masterclass.com everywhere. This episode is sponsored by Butcherbox. You've probably heard me talk about how ButcherBox only sells 100% grass fed grass finished beef, but what exactly is that and why does it matter? This type of beef comes from cattle that have grazed on grass for their entire lives as opposed to being finished on a diet of grains and other feed at a feedlot. Basically, cattle eat what cattle are designed to eat. Grass fed beef tends to have higher levels of omega 3 fatty acids and grass fed beef often contains more antioxidants such as vitamin E. Beyond personal health benefits, choosing grass fed grass finished beef can also improve soil health through natural fertilization and aeration and can also promote greater biodiversity on grazing lands. Consuming grass fed grass finish beef not only contributes to better health but also supports more sustainable farming practices. Sign up@butcherbox.com daily and get a special deal. New users who sign up for Butcherbox will receive 2 pounds of grass fed ground beef in every box for the lifetime of their subscription plus $20 off your first box when use code daily at checkout. Let's start out with the basics and answer the question what is sand? We all know when we see it, but how is it actually defined? Sand isn't a substance per se. There isn't one type of sand. Sand is a term that covers a wide variety of sedimentary particles of a given size. To understand how sand is classified, it's important to understand the Wentworth Scale. The Wentworth Scale and its modification, known as the Crumbene Phi scale, is a widely used system for classifying sedimentary particles based on their size. It was developed by an American geologist, Chester k. Wentworth, in 1922 as a modification of earlier systems to provide a standardized framework for describing grain sizes in sediments and sedimentary rocks. The Wentworth scale covers every sort of particle from the very large to the very small. Anything with a diameter greater than 256 millimeters is considered to be a boulder. Anything between 64 and 256 millimeters is called cobble. This would be about the size of a river stone you might use for skipping rocks. Anything from 2 to 64 millimeters are considered pebbles. And finally, anything from 0.0625 to 2 millimeters is sand, and below sand on the scale is silt and clay. Sand can further be subdivided into very coarse, coarse, medium fine, and very fine sand. And that is all that sand is. Any rock or mineral that has a diameter between 0.0625 and 2 millimeters is sand. Sand and other sedimentary particles are created through a series of natural processes that break down larger rocks and minerals into smaller fragments. This process begins with weathering, the breaking down of rocks at or near the Earth's surface. Weathering occurs in three main physical, chemical, and biological. Physical weathering involves mechanical forces, such as the expansion of water when it freezes in rock cracks, causing the rock to fracture or abrasion, where rocks grind against each other due to wind, water or ice. Over time, these actions produce smaller and smaller particles. Chemical weathering transforms rocks by altering their mineral composition through reactions with water, oxygen, or other chemicals. For example, hydrolysis occurs when water reacts with minerals like feldspar, converting them into clay and soluble compounds. Similarly, oxidation causes iron rich minerals to form rust, like substances breaking down the rock. Biological weathering, the third type, occurs when organisms such as plants and lichens physically break apart rocks or chemically alter them by secreting acids. Once the rocks are broken down into smaller pieces, erosion removes these particles from their original location. Erosion is driven by forces such as water, wind, ice and gravity. Erosion is different from weathering in that it involves the movement of particles, whereas weathering does not. For example, flowing rivers and streams carry sediment downstream while wind transports fine particles like sand and silt across deserts, glaciers moving massive sheets of ice scrape and grind the underlying rock, transporting the resulting particles far from their source. Waves can also move and erode sand along shores and coastal areas. The important thing to understand is that the process of weathering and erosion is going to be different for every collection of sand, depending on where in the world you find it. While any rock or mineral of the right size can be considered sand, there are some types of sand that are very common all over the world. And the most common mineral that winds up as sand is quartz. Quartz is the most common mineral in sand due to its abundance in the Earth's crust and its resistance to weathering. Quartz is a very hard mineral. It's a 7 on the Mohs hardness scale, which makes it much harder and much more difficult to erode than most other minerals. You'll usually find quartz sand where you find continental crust. Quartz sands are frequently found on beaches, particularly in regions with extensive weathering of continental rocks like granite. The high energy of waves and currents often remove lighter or softer minerals, concentrating the durable quartz grains. Most deserts contain a high amount of quartz. The Sahara Desert contains areas with significant quartz sand, as does the Namib Desert in Africa, for example. White sand beaches like those in Siesta Key, Florida, or Whitehaven beach in Queensland, Australia, are famous for their nearly pure quartz sand, which is also known as silica. Fraser island in Australia is known for some of the purest quartz sand dunes in the world. However, not all white sand beaches are made out of quartz. If you go to a tropical island, you may see a white sand beach. And these beaches are almost never made out of quartz. They're made out of calcium carbonate, which is also white. This type of sand primarily originates from biological processes and the breakdown of marine organisms. Coral, seashells and plankton exoskeletons are all made out of calcium carbonate. When these organisms die, their shells and skeletons break apart due to wave action, predators or decay. And over time, the fragments are ground into finer particles, forming sand. There are also other types of white sand. White Sands national park in New Mexico has sand made out of gypsum, which is also white. This type of sand is very rare and only found where you have exposed gypsum deposits. Other types of rare sands can be found all over the world as well. Black sand can be found in places with active volcanism. This comes from the erosion of black volcanic basalt rock. There are black sand beaches that can be found in Hawaii, the Canary Islands, Italy, Bali, French Polynesia, and many other places. There are four places in the world where you can find green sand, the most famous of which is the greensand beach on the Big island of Hawaii. There are also greensand beaches in Guam, Ecuador and Norway. The green sand comes from the mineral olivine. Olivine is very common in the earth's mantle, but much rarer on the surface. It comes to the surface through volcanoes. The Greensand beach in Hawaii is the remnants of a cinder cone with a high level of olivine. And there's also an amber variant of olivine which can be found with the green. But the green is what it's famous for. On the island of Maui, there's a red sand beach that can be found not far from the town of Hana. The red is rust that comes from the iron rich basalt found nearby. If the iron content was less, the beach would be black instead of red. Pink sand beaches are rare coastal areas where the sand has a distinct pinkish hue. The color comes primarily from tiny fragments of foraminifera, which are marine organisms with reddish pink shells made of calcium carbonate. These shell fragments mix with standard sand particles, often alongside crushed coral and other marine debris, creating the soft pink coloration. These beaches are typically found in tropical regions near coral reefs, such as the Bahamas and Bermuda. As you are well aware, sand can form dunes. Dunes have unique properties that are probably worth an episode of their own at some point. Dunes are not static formations. They are always slowly moving. As winds blow sand, they can sometimes move as much as several meters a year, and over centuries, they can change completely. Singing sand dunes, also known as booming dunes, are a natural phenomenon where sand emits a deep resonant hum or booming sound when it moves. This occurs when large amounts of dry, well sorted sand grains slide down the steep slopes of a dune under specific conditions. The sound is caused by the friction between the sand grains, creating vibrations that resonate through the dune. The pitch and tone of the sound depends on factors such as the size and shape of the grains, moisture content and the speed of movement. Singing dunes are rare and can be found in deserts around the world, including the Sahara, Gobi and Namib deserts. As I mentioned in the introduction, sand is the world's second most used natural resource behind water. However, most of us don't really think of sand as a resource. Nonetheless, it's used for a wide variety of purposes. High purity silica sand is melted to create glass for windows, bottles and screens. Likewise, silica sand is used to manufacture optical fibers for telecommunications. Ultrapure quartz sand is refined to extract silicon, a Critical material in semiconductors for electronics like computers and smartphones, sand is used in making tiles, pottery, and other ceramic products. Foundries use sand molds to shape molten metal into precise forms. Sand is also a natural filter used in water purification systems and aquifers. The single largest use for sand, however, is in the construction industry. Sand plays a critical role in construction as a primary ingredient in essential building materials such as concrete, mortar, and asphalt. In concrete, sand is combined with cement and gravel to form a durable, versatile material used in construction projects, bridges, roads, and dams. Mortar, a mix of sand and cement, binds bricks, stones, and other materials in masonry. Sand also provides bulk and strength to construction materials, improving their structural stability. Additionally, it's used as a base material in road construction, as a filling material in land reclamation, and as a leveling agent beneath foundations and pavements. However, there is a problem with the construction industry's use of sand. We're running out of it. Now, this might seem absurd at first because we have deserts full of sand. It's almost like saying we're running out of seawater. Nonetheless, we are running out of sand because you can't just use any old sand for construction, especially for creating concrete. Desert sand is not suitable for construction because its grains are too smooth and rounded, a result of wind erosion that polishes the particles over time. These smooth grains lack the angular edges needed to create strong mechanical bonds with cement and concrete, leading to weaker structures. Additionally, desert sand is often too fine and uniform in size, which prevents it from achieving the proper density and stability required for construction materials. In contrast, river or quarry sand has angular grains and a mix of particle sizes, making it ideal for creating durable and strong concrete and mortar. The construction boom, particularly in fast growing economies like India and China, has created immense demand for sand. Most of the sand used for construction comes from sand mining, usually on beaches and riverbeds. However, easily accessible sources of the right kind of sand are running out, and this has resulted in a surge in illegal sand mining. And it's become a big business for organized crime. These criminal networks, often referred to as sand mafias, operate in countries like India, Kenya, and Cambodia, where they exploit poorly regulated or protected areas such as riverbeds, beaches, and coastal zones. They extract sand in large quantities, bypassing environmental laws and not paying taxes. Their operations frequently involve violence, intimidation, and corruption, targeting activists, journalists, and officials who oppose illegal sand mining. Sand can be found almost everywhere around the world, albeit in very different forms. It plays a vital role in everything from geology to biology to industry, and even, it appears, organized crime. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Benji Long and Cameron Keever. I want to give a big shout out to everyone who supports the show over on Patreon, including the show's producers. Your support helps me put out a show every single day, and also Patreon is currently the only place where Everything Everywhere Daily merchandise is available to the top tier of supporters. If you'd like to talk to other listeners of the show and members of the Completionist Club, you can join the Everything Everywhere Daily Facebook group or Discord server. Links to Everything are in the show Notes.