Types of sand are numerous across the globe. While sand is ubiquitous across the world, the exact nature of sand depends on the environment that produces it. All sand is composed of small particles of rock and organic matter, but each type has distinct characteristics and properties.
From white sandy beaches to ruddy desert dunes, sand has shaped the way that humans live their lives because of the diverse environments in which it exists. Understanding distinct types of sand can teach us more about the environment that created them and help us learn how we can support the ecosystems in which we all thrive.
Types of Sand by Origin or Use
Sand is classified into distinct types based on its origin, composition, and purpose. Here are some of the most common types of sand:
Beaches are famous for their fine-grained sand ranging in color from white to golden or even black. Sand forms along beaches because of the constant erosion of the waves on rocks and shells in the sea. The movement of water washes the sand along the shore of the waves. Most of these sands contain quartz, though other minerals and shells contribute to their unique characteristics on beaches around the world. Beach sand is vital in the protection of inland coastal ecosystems.
Desert sand is a feature of arid parts of the world. Unlike coastal regions shaped by water, desert sand is formed by wind erosion. Wind erosion creates a fine, round, and smooth-shaped sand particle that blows freely and creates a constantly changing landscape. Desert sand is particularly unsuitable for construction because of its fine texture and smooth shape. Desert sand contains quartz and feldspar. Sand in some desert regions has high amounts of iron oxide which give it a reddish hue.
Deserts are a harsh ecosystem but can support a variety of life including plants such as cacti, succulents, desert grasses, and tamarisks, and animals such as camels, lizards, snakes, fennec foxes, and kangaroo rats.
River sand is a result of the constant flow of water in rivers or streams and its erosion on rocks. As the river flows, it carries the sand to the banks of the river, the floodplain, or the delta region where the river meets a larger body of water. The constant rubbing of the water results in smooth and well-sorted grains of sand.
River sand contains quartz, feldspar, and mica. River sand is the most common type of sand that builders use in construction. Excessive mining of river sand can cause erosion along the river bank which can damage the ecosystems in that environment.
Volcanic sand originates from volcanic activity that expels fragmented pieces of lava and ash into the atmosphere. These fragments cool and solidify as they travel through the air and fall back to the ground as fine-grained sand particles. Volcanic sand has unique characteristics that set it apart from other sand types. Volcanic sand has dark-colored particles, typically black, gray, or reddish brown with irregular and angular proportions. Balsat, obsidian, pumice, and volcanic glass are the common components of volcanic sand.
You can find volcanic sand in areas with volcanic activity including volcanic islands, plateaus, and regions with both active and dormant volcanoes. Because of its unique properties and minerals, people use volcanic sand in skin care products, soil mixes, and construction.
Coral sand originates from the natural process of growth, erosion, and fragmentation of coral reefs. Coral reefs have colonies of coral polyps that secrete calcium carbonate to build their hard exterior skeleton. Over time, these exoskeletons erode or fragment and form sand.
This sand has a white to pink color and a smooth and soft texture. Coral sand predominates in tropical regions near coral reefs or islands. Due to its alkalinity, coral sand helps to preserve a healthy natural ecosystem in these environments.
Silica sand, also called industrial sand, is a naturally occurring type of sand that contains a high amount of pure silica. Manufacturers extract high-silica sand through mining along riverbeds, beaches and dunes.
Industrial sand grains are well-rounded and have a uniformity of shape and size that makes them useful in various industries including glassmaking, foundry casting, fracking, concrete and mortar production, filtration, and abrasive blasting.
Play sand is particularly formulated to produce a safe and toxin-free substance for children’s use. Play sand has a fine-grained texture with rounded edges to ensure that it is gentle on the skin. Manufacturers wash the sand to remove any impurities or hazardous material such as asbestos or silica dust.
Manufacturers also create specialized sand types for specific applications including sports turf sand, horticultural sand, refractory sand, and colorized sand. Unlike natural sands, specialized sands are enhanced with chemicals, washed to remove impurities, and screened to collect granules with distinct minerals and size particles.
Types of Sand by Color
Sand exists in diverse colors all over the world. The color of a type of sand signifies the presence of certain minerals and organic material and also the environment that produced it.
- White sand – White sand has a light and bright white color. Many people favor white sand beaches because of their pristine and pure look. White sand contains quartz or coral fragments weathered from granites, quartz-rich rocks, and coral reefs. This type of sand is common in tropical beach destinations like the Caribbean, the Maldives, and Southeast Asia.
- Golden sand – Golden sand has a soft yellow to golden-brown color. It gets its color from certain minerals such as hematite and magnetite which are rich in iron. The golden sand is a feature of many beaches worldwide, especially those near mineral-rich rock formations.
- Black sand – Black sand is a result of volcanic activity and indicates the presence of obsidian and basalt. Black sand is rich in heavy minerals such as magnetite and ilmenite. Because of the many years of volcanic activity and eruptions, black sand is a common feature in coastal areas near volcanic activity, both dormant and active.
- Red/orange sand – Red or orange sand has a distinct light to dark reddish-brown hue. Minerals such as hematite and magnetite are rich in iron ore and produce this deep red color. Because of its high iron content, red sand can have magnetic properties. You can find red or orange sand in both desert and coastal regions with high concentrations of iron-rich rocks.
- Pink sand – Pink sand gets its unique color from a combination of white sand with crushed coral, shells, and calcium-carbonate-rich marine organisms such as foraminifera. Coralline algae is another significant factor in the formation of pink sand.
- Purple sand – Naturally occurring purple sand contains purple-colored minerals such as manganese or rose quartz. Purple sand is one of the more rare types of natural sand. You can find purple sand in certain parts of Canada and the United States.
- Green sand – Green sand exists in many forms and each type has different minerals and properties. Two types of green sand are greensand and olivine sand. Greensand contains the mineral glauconite. It is commonly used as a soil conditioner and natural fertilizer because of its ability to enhance plant growth and absorb and exchange ions. Olivine sand has an olive green color. You can find olivine sand in volcanic and coastal regions with olivine-rich rocks.
Type of Sand by Grade
One common scale for defining the type of sand based on the size of the particles was developed by geologist, W.C. Krumbein in the 1930s. He developed a logarithmic scale that he used to classify the wide range of particle sizes into understandable grades. Sand grades are vital for builders and landscapers because they help define the appropriate uses for sizes of sand and explain how the sand aggregate will behave in a given circumstance.
The United States uses the Krumbein phi scale to classify sand into five sub-categories: very fine, fine, medium, coarse and very coarse.
- Very fine sand – Very fine sand ranges between 0.0313 mm to 0.0625 mm in diameter.
- Fine sand – Fine sand ranges between 0.0625 mm to 0.125 mm in diameter.
- Medium sand – Medium sand ranges between 0.125 mm to 0.25 mm in diameter.
- Coarse sand – Coarse sand ranges between 0.25 mm to 0.5 mm in diameter.
- Very coarse sand – Very coarse sand ranges between 0.5 mm to 1 mm in diameter.