Rocks and minerals ID

A flashcard set with the names of rocks and minerals.

Obsidian

Obsidian is a naturally occurring volcanic glass formed from the rapid cooling of lava without crystallization. It is typically black or dark in color and has a smooth, glassy texture.

Geneiss

A metamorphic rock formed from the alteration of granite or sedimentary rocks under high temperature and pressure, characterized by its coarse-grained texture.

Limestone

Limestone is a very common type of stone that forms under water. It is a sedimentary rock, which means it is made from layers of tiny pieces that pressed together over millions of years. It is mostly made of a mineral called calcite, which contains calcium

Scoria

Scoria is a dark, heavy-looking rock that is full of holes and forms during violent volcanic eruptions. It is an igneous rock, which means it comes from hot, melted liquid rock called magma.

Quartzite

Quartzite is an extremely hard, tough rock that forms when sandstone is baked by intense heat and squeezed by heavy pressure deep inside the Earth. It is a metamorphic rock, which means it is a rock that completely changed from its original form into a new one.

Magnetite

Magnetite (Fe₃O₄) is a highly magnetic iron oxide mineral and the primary mined ore of iron, boasting the highest iron content (72.4%) of any naturally occurring mineral. It is famous for its unique ferrimagnetic properties, meaning it is strongly attracted to magnets and can be permanently magnetized itself.

Hornblende

Hornblende is a dark-colored, complex silicate mineral that belongs to the amphibole family. It is not a single specific mineral, but rather a catch-all field term used by geologists to describe a group of dark green, dark brown, or black minerals that share very similar properties.

Pyroxene

Pyroxenes are a large group of dark, rock-forming minerals found all over the world. They are key parts of many igneous rocks (made from cooled magma or lava) and metamorphic rocks (changed by intense heat and pressure).

Plagioclase

Plagioclase is a group of very common minerals that make up a large part of the Earth's crust. It belongs to a larger family of minerals called feldspar. Instead of being just one single mineral, plagioclase is a mix of two different ingredients that blend together.

Hematite

Hematite is a common mineral made of iron oxide that serves as our planet's main source of iron. Its chemical formula is Fe₂O₃, which means it is mostly made of iron and oxygen. People love hematite for its heavy feel, shiny metallic look, and long history in art and science.

Flourite

Fluorite is a beautiful, colorful mineral made of calcium and fluorine. It is famous for its perfect cube and double-pyramid shapes. Pure fluorite is clear, but tiny impurities make it glow in almost every color of the rainbow, with a hardness of 4 on the Mohs scale.

Granite

Granite is a hard, light-colored igneous rock that forms deep underground. It is one of the most common rocks on Earth and makes up a huge part of the land we walk on.

Pyrite

Pyrite is a shiny, brass-colored mineral that people often mistake for real gold. Because its metallic look has tricked so many people over the years, it is famously nicknamed "Fool's Gold".

Shale

Shale is a fine-grained, clastic sedimentary rock formed from the compaction of mud, silt, and clay mineral flakes. It is the most abundant sedimentary rock on Earth, accounting for roughly 70 percent of the sedimentary crust. Its most defining feature is fissility, meaning it readily splits into thin, flat, parallel layers less than one centimeter thick.

Basalt

Basalt is a dark, heavy volcanic rock that forms when lava cools quickly on the Earth's surface. It is the most common rock type on Earth. It makes up most of our ocean floor.

Pumice

Pumice is a very light, rough volcanic rock that is full of tiny holes. It is unique because it is so lightweight that it can actually float on water. People use pumice every day for skincare, cleaning, and gardening.

Coal

Coal is a combustible black or brownish-black sedimentary rock composed primarily of carbon and hydrocarbons, used globally as a major nonrenewable fossil fuel. It forms over millions of years through the heat and deep burial pressure of decaying plant matter in ancient, low-oxygen wetland environments. While coal historically powered the Industrial Revolution and remains a significant contributor to the global energy grid, its intensive carbon dioxide emissions and environmental footprint make it a central focus of modern climate and clean energy debates.

Sandstone

Sandstone is a common sedimentary rock made of tiny grains of minerals and rock, mostly quartz and feldspar. Over millions of years, water presses these grains together, and minerals glue them into solid stone. It is very popular for building houses, making beautiful art, and decorating gardens.

Marble

Marble is a metamorphic rock that forms deep inside the Earth. It starts out as a completely different kind of rock—usually limestone—before being baked by extreme heat and squeezed by immense pressure.

Slate

Slate is a fine-grained, foliated metamorphic rock derived from sedimentary shale or mudstone. Squeezed by intense geological forces, its minerals align into flat layers, giving slate its signature ability to be split into thin, durable sheets.

Copper

Native copper holds a unique place in geology because it is one of the only metals that nature delivers in a raw, pure form. Humans do not need to smelt or chemically separate it from other stones to use it.

Silver

Silver is a rare, shiny precious metal that can be found in nature as a pure mineral or mixed inside other rocks. Known officially as Native Silver when found pure, it has the highest electrical and thermal conductivity of any metal. While people have mined it for thousands of years for coins and jewelry, pure silver nuggets are actually very rare. Most silver today is found combined with other elements like sulfur or hidden inside copper and lead ores.

Gold

Gold is a rare, naturally occurring mineral made of just one chemical element: gold (Au). Scientists group it as a native element because it is found in nature in its pure metal form rather than being locked up inside a chemical compound with other elements.

Mercury

Pure liquid mercury is technically not a mineral, because a true mineral must be a solid crystal. Instead, scientists call pure liquid mercury a mineraloid. However, mercury is found inside real, solid rocks and minerals in the Earth's crust.

Nickel-Iron

A nickel-iron mineral is a natural mix of nickel and iron metals. Scientists call these mixes native alloys. Most of these minerals come from outer space as meteorites. They are also found deep inside the Earth.

Platinum

Platinum is a very rare, heavy, and valuable mineral that looks like shiny, silver-gray metal. Scientists call it a "native element" because it can be found in nature in its pure metal form, instead of being mixed inside a stone with other elements.

Arsenic

Arsenic is a naturally occurring element that is rarely found in its pure form. Instead, it usually combines with other elements like sulfur, iron, and oxygen to form over 150 different minerals. These minerals can look like bright, colorful crystals or dull, gray rocks.

Antimony

Antimony is a unique chemical element and metalloid that is rarely found in its pure form in nature. Instead, it is almost always locked inside other rocks and minerals.

Bismuth

Bismuth is a heavy, silvery-white metal mineral known for its slight pink tint and its ability to form stunning, rainbow-colored crystals when grown in a lab. While it is a naturally occurring chemical element, pure "native bismuth" is actually very rare in nature. Instead, it is usually found combined with other elements inside ores or collected as a byproduct when mining metals like lead and copper.

Graphite

Graphite is a naturally occurring mineral made of pure carbon. It has the exact same chemical makeup as a diamond, but its atoms are arranged differently. This unique layout makes graphite one of the softest minerals on Earth, while a diamond is the hardest.

Diamond

Diamond is a rare, naturally occurring mineral made of pure carbon. It is famous for being the hardest natural substance on Earth. Because its atoms are packed incredibly tight, it has unique traits that make it highly valuable for both beautiful jewelry and heavy-duty industrial work.

Sulfur

Sulfur is a bright yellow mineral that is famous for its distinct, rotten-egg smell when heated. It is a native element, which means it is made of only one type of atom: sulfur (S). You can learn more about it on the Sulfur Wikipedia Page.