# Minerals - Source: Kiddle (kids.kiddle.co), CC BY-SA 3.0, Kiddle encyclopedia, adapted from Wikipedia - Reading level: Grade 5 - Subjects: Rocks and Earthquakes, Nature, Science - Topics: minerals, mineral, different, structure, called, crystal - Length: 1211 words, about 9 min - Published: 2026-06-10 - Original: - Page: - Open in Sprouts: A **mineral** is a naturally occurring solid substance with a specific chemical recipe and an orderly arrangement of its atoms. Think of minerals as the fundamental building blocks of our planet! Minerals are different from [rocks](https://sprout.rootsofreason.org/r/kiddle/rocks). A rock is usually a mixture of one or more minerals, or even other materials. For example, granite is a rock made of several different minerals like quartz and feldspar. But a mineral, like quartz, is a single, pure substance. Some natural solids, like opal or obsidian, don't have that perfect, orderly atomic structure. These are called mineraloids, not true minerals. If a chemical compound can form with different crystal structures, each unique structure is considered a different mineral. For instance, quartz and stishovite are both made of silicon dioxide, but they are different minerals because their atoms are arranged differently. The International Mineralogical Association (IMA) is the official group that names and defines minerals. As of June 2026, they recognize over 6,145 different mineral species! A mineral's chemical makeup can vary slightly due to tiny amounts of other elements, called impurities. For example, amethyst is a purple type of the mineral quartz. Some minerals can even have different amounts of certain elements that swap places in their structure, like the olivine group, which can be rich in either magnesium or iron. Scientists describe minerals using many features. These include their shape (called habit), how hard they are (their hardness), how shiny they look (their lustre), how much light passes through them (their diaphaneity), their colour, the colour of their powder (their streak), how they break (their cleavage or fracture), and how heavy they feel for their size (their specific gravity). Some minerals even have special traits like magnetism, fluorescence, or radioactivity. Minerals are sorted into groups based on their main chemical ingredients. The most common minerals in the Earth's crust are silicate minerals, making up about 90% of it! Other important groups include native elements (like pure gold), sulfides (like galena), oxides (like quartz), halides (like rock salt), carbonates (like calcite), sulfates (like gypsum), and phosphates. ## What Makes a Mineral? The International Mineralogical Association (IMA) has clear rules for what counts as a mineral. ### Natural and Solid A substance must be found in nature, formed by geological processes on Earth or even other planets. This means things made only by humans or living creatures (like seashells) are usually not minerals. However, if geological processes later change these substances, they might become minerals. Minerals must also be solid in their natural state. A famous exception is native mercury, which is liquid at room temperature but was classified as a mineral before the rules were set. Water ice is considered a mineral because it's a solid with a crystal structure. ### Orderly Structure and Chemistry Minerals must have a clear, ordered arrangement of their atoms, like a repeating pattern. This gives them properties like a specific shape and hardness. Materials without this order, like obsidian (volcanic glass), are called mineraloids. Minerals also need a fairly defined chemical recipe. Some minerals can have a range of compositions, where one element can swap places with another. For example, mackinawite can have varying amounts of iron and nickel. Sometimes, minerals with a continuous range of compositions are divided into separate species, like the olivine group, which includes both magnesium-rich and iron-rich types. ### Minerals from Living Things Some scientists believe that minerals formed by living organisms, called biominerals, should also be included. Organisms can create many different minerals, some of which don't form in other ways. For example, tiny microorganisms can help create minerals in rocks and soil. Even though the IMA has strict rules, the study of how life and minerals interact is a growing field! ## Rocks, Ores, and Gems: Mineral Connections ![Sillimanite-199671](https://sprout.rootsofreason.org/media/kiddle-minerals-4ea33f6fa1.jpg) Schist is a metamorphic rock with many flat minerals. This example shows large sillimanite crystals up to 3 cm (1.2 in) long. A [rock](https://sprout.rootsofreason.org/r/kiddle/rocks) is a natural solid material made of one or more minerals or mineraloids. Some rocks, like limestone, are mostly one mineral (calcite). Others, like granite, are a mix of several minerals. Minerals that make up most rocks are called *rock-forming minerals*, such as quartz, feldspars, and micas. *Industrial minerals* are valuable minerals and rocks used in industries, but they are not gemstones or metal ores. For instance, muscovite (a type of mica) can be used in windows or as an insulator. *Ores* are minerals that contain a high amount of a specific element, usually a metal, making them valuable to mine. Examples include cinnabar (for mercury) and sphalerite (for zinc). *Gems* are minerals prized for their beauty, durability, and rarity. There are about 20 main types of gem minerals, but they come in many varieties. For example, both ruby and sapphire are types of the mineral corundum. ## Where Did the Word "Mineral" Come From? The word "mineral" first appeared in the English language around the 15th century. It comes from a medieval Latin word, *minerale*, which means "mine" or "ore." The word "species" comes from the Latin word *species*, meaning "a particular sort or kind." ## Mineral Chemistry: Earth's Building Blocks ![Hubnerite-Quartz-216455](https://sprout.rootsofreason.org/media/kiddle-minerals-f5e941f130.jpg) Hübnerite, a manganese-rich mineral, with some quartz in the background. The types and amounts of minerals we see depend on the chemical elements available in the Earth. Most minerals come from the Earth's crust. Eight elements make up over 98% of the crust by weight: oxygen, silicon, aluminium, iron, magnesium, calcium, sodium, and potassium. Oxygen and silicon are the most important, making up 47% and 28% of the crust, respectively. Minerals form when elements combine in ways that are most stable at certain temperatures and pressures. For example, in many volcanic rocks, aluminum and alkali metals (sodium and potassium) combine with oxygen, silicon, and calcium to form feldspar minerals. If there's too much of one element, different minerals might form. Minerals can also have slightly different chemical recipes within the same type. For instance, plagioclase feldspars range from sodium-rich albite to calcium-rich anorthite. This happens because similar-sized atoms can sometimes swap places in the mineral's structure. ## How to Identify Minerals: Physical Properties Identifying minerals can be easy or challenging. Sometimes, a few simple tests are enough. Other times, scientists need special equipment like X-rays. Here are some common physical properties used to identify minerals: ### Crystal Structure and Shape ![Topaz-235220](https://sprout.rootsofreason.org/media/kiddle-minerals-52d219e260.jpg) Topaz often has a distinct elongated crystal shape. A mineral's crystal structure is the orderly, repeating arrangement of its atoms. This internal structure often shows up in the mineral's external shape, called its crystal habit. Even if the crystals are tiny, their internal structure is always regular. Minerals are grouped into six main crystal families based on their symmetry: | Crystal family | Example Minerals | | --- | --- | | Isometric | Garnet , halite , pyrite | | Tetragonal | Rutile, zircon , andalusite | | Orthorhombic | Olivine , aragonite, orthopyroxenes | | Hexagonal | Quartz , calcite , tourmaline | | Monoclinic | Clinopyroxenes , orthoclase, gypsum | | Triclinic | Anorthite, albite, kyanite | Minerals with the same chemical formula but different crystal structures are called polymorphs. For example, diamond and graphite are both made of pure carbon, but their atoms are arranged very differently, giving them vastly different properties. Diamond is super hard and shiny, while graphite is soft and greasy. Sometimes, two or more crystals of the same mineral can grow together in a special way called twinning. This creates interesting patterns, like the cross-shaped crystals of staurolite. ## Picture credits - Robert M. Lavinsky, CC BY-SA 3.0 () - Robert M. Lavinsky, CC BY-SA 3.0 () - Robert M. Lavinsky, CC BY-SA 3.0 ()