Fine rock and mineral particles make up the granular aggregate known as sand. It is an essential building material that is required for the production of concrete. Sand’s makeup and color vary according to the types and locations of the surrounding rock formations. Silica is the primary component of sand in inland continental environments. Calcium carbonate sand is the second most typical kind of sand.
The following table indicates the particle size distribution. As it states, coarse sand, medium sand, and fine sand are the main categories based on their size. The particle size of the sand varies between 2.0 – 0.06mm.
| Particle size class | Size/(mm) |
| Boulders | >200 |
| Vary coarse gravel | 200-60 |
| Coarse gravel | 60-20 |
| Medium gravel | 20-6 |
| Fine gravel | 6-2 |
| Coarse sand | 2.0-0.6 |
| Medium sand | 0.6-0.2 |
| Fine sand | 0.2-0.06 |
| Silt | 0.06-.002 |
| Clay | <0.002 |
Sand is a granular substance that consists of tiny mineral fragments. The content of sand varies, but the grain size is what distinguishes it. As shown in the above table, sand grains are smaller than gravel and coarser than silt.
Types of Sand
Sand can be classified under two main categories. They are;
- Based on the Color of the Sand
- Based on Production or Formation
In addition, another classification is also there as indicated in the above table. It is based on particle size. Coarse sand, medium sand, and Fine sand are the three main categories.
Some other types of sand are coral sand, glass sand, immature sand, gypsum sand, etc. These will be discussed in the latter part of this article.
Sand Types Based on Color
Sand can be classified based on its color. The most commonly known types of sand are;
1. White Sand
The white sand can be mostly observed on beaches. Quartz-rich sediments are frequently found in white sand beaches. Quartz is a tough material that is challenging to weather and erodes due to its chemical composition. As a result, quartz is frequently the most common mineral in beach sands. Accessory minerals including garnet, magnetite, and ilmenite are frequently found on white sand beaches. These minerals are frequently discovered near coastlines in dark streaks, which show how heavier minerals were sorted out by wind and waves.
2. Black Sand
Black sand is known as black sand. A placer deposit may contain black sand, which is a heavy, glossy, partly magnetic mixture of typically fine sands containing minerals like magnetite. Small pieces of basalt make up another sort of black sand that can be discovered on beaches close to volcanoes.
3. Pink Sand
Pink sand can be observed on beaches. The almost indescribable pale pink hue of the sand is produced by tiny coral insects called foraminifera, which have a shell that is bright pink or red and punctured with holes through which they extend pseudopodia, or feet, which they use to attach themselves to surfaces and feed.
4. Orange Sand
Iron-rich minerals can also give sand an orange color. Sands can take on an orange hue when combined with orange limestone, volcanic deposits, and marine organisms’ shells.
5. Red Sand
A considerable amount of weathered iron is present nearby if the color is reddish. Rust, also known as iron oxide, is a product of the reaction between iron and oxygen. Sand can take on a variety of red hues depending on the number of iron oxide minerals hematite and goethite present.
6. Green Sand
Green sand has a greenish color. This phrase is used to refer specifically to shallow marine sand that has a considerable amount of spherical, greenish grains. The mixed-layer clay minerals smectite and glauconite mica make up these grains, which are known as glauconite. Any glauconitic sediment is also loosely covered with greensand.
7. Purple Sand
Almandine-pyrope garnet or other purple minerals like manganese or rose quartz that have accumulated in the local sediment are the primary causes behind the phenomena of purple sand beaches. Typically, near a major river system with coarse sediment, a glacial sediment source, or input from glacial or para-glacial silt, these purple beaches can be found.
In addition, sand can be classified based on its formation and existence. This is the most commonly used method to identify the sand. Further, these types of sand are used for construction work mostly.
Sand Types Other Classification
River Sand
The majority of the sand used in the building industry comes from rivers, either from the river itself or its floodplain. As a result, many minor rivers have become drained, raising concerns about the ecology and resulting in economic losses for nearby territories. Sand is a non-renewable resource in certain locations because the rate of mining far outpaces the rate of sand replenishment.
Sea Sand
Due to the depletion of current supplies, the construction industry is investigating alternatives such as sea sand. Using sea sand for construction could be one of the greatest options if it is cleaned properly.
A shortage in the availability of construction materials has resulted in rising demand. Furthermore, it has been noted that several projects have been delayed as a result of the late arrival of materials. A reliable source of materials is also getting harder to get these days. As a result, the usage of sea sand that is suitable for construction is growing in popularity.
Molding Sand
Molding sand, commonly referred to as foundry sand, is a type of sand that likes to pack tightly and maintain its shape when moistened, squeezed, greased, or heated. It is used to prepare the mold cavity during the sand-casting process.
Foundry sand, commonly referred to as molding sand, is sand that when damp seashores, rivers, lakes, deserts, and granular parts of rocks are the typical sources of molding sands. Molding sands can be broadly categorized into two categories: natural and synthetic.
Natural molding sands have an adequate amount of binder. In contrast, synthetic molding sands are made artificially by mixing and blending the basic sand molding ingredients (silica sand in proportions of 85–91%, binder in proportions of 6–11%, water or moisture content in proportion to 2-8%) in the right amounts.
Manufactured Sand
River sand can be substituted with manufactured sand. Due to the rapidly expanding building sector, there is a severe lack of adequate river sand across the majority of the world.
The usage of artificial sand has expanded as a result of the shortage of high-quality river sand used in buildings. The accessibility and expense of shipping M-Sand are other justifications for its use. Since manufactured sand can be made by crushing strong granite rocks, it can be easily found nearby, saving on transportation costs from distant river sand beds.
Washed Sand
The washing process gets rid of the sand of clay, silt, dust, and other undesirable particles. Sand is allowed to drain once extra materials have been taken out of the way. Sand that has been washed is good for rendering, concrete mixing, and creating a less malleable mortar that is frequently used for flagstones.
Washed sand is used for rendering and flooring works, laying paving, landscaping, etc. It is required to put the highest attention when washed sand is used for concrete work. Generally, it is not recommended to use the washed and for the structural concreting work as we cannot guarantee that sand is free from the other materials.
Mason Sand
Mason sand is a fine sand that is frequently used in building construction. It is also known as masonry sand or mortar sand. This sand has uniformly sized granules that give it a smooth appearance and feel. Its name comes from the fact that masonry construction is one of its primary uses. Mason sand, on the other hand, is incredibly adaptable and useful for a variety of tasks.
Many various home and landscape projects call for masonry sand. Despite having the same quarry rock composition as other sands, it has undergone thorough processing to produce a fine, homogeneous texture.
Silica Sand
Silica and oxygen are the two primary components of silica sand, commonly referred to as quartz sand, white sand, or industrial sand. The material must contain at least 95% SiO2 and less than 0.6% iron oxide to be classified as silica sand; otherwise, it will be categorized as ordinary sand.
When compared to silica sand, ordinary sand has a deeper hue and is more chemically reactive because of the impurities. Regular sands come in a variety of colors, including white, pink, green, and black, depending on the geology and location of the sand deposit.
