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Fluorite is really interesting! When you find it in a rock, all the little crystals will usually be in the shape of cubes. This is the way that the mineral naturally grows!

Fluorite is a soft rock which can be scratched with a common nail (ask your parents for help with this). Some people even like to carve it into sculptures. Fluorite can be found in many different colours.

But the coolest thing about fluorite is that it is fluorescent! What does this mean? It means that if you have an ultraviolet light/ a black light (the lights that they use in glow in the dark mini-putt that look purple) and you shine it on the rock then it will glow!!! Fluorite from two different places might glow two different colours under the same light.
Used in:

Toothpaste: Fluoride is one of the main elements in fluorite. It helps prevent and sometimes reverse the early stages of tooth decay

Drinking water: Fluoride is also found in drinking water! Don't worry, it's good for your teeth and won't hurt you in small doses

Copper

Have you ever had a ring that turned your finger green? If so, it was probably made out of copper!

Copper is a natural metal. It absorbs heat very easily which is why we sometimes use it to make pots and pans for cooking. We use it in electrical wires too because electricity flows through it really easily.

Copper is one of only two coloured metals (the other is gold). It is usually a reddish brown colour but it turns green when it's exposed to air for a really long time (think of the green colour as a form of rust).
Used in:

Pennies

Electrical wires

Water Pipes

The Statue of Liberty is made of copper, and all the parliament roofs in Ottawa (the green roofs) are made of copper too.

It's strange to think about, but we eat copper sometimes! A little bit of it is actually good for us. It is found in hot chocolate powder, chocolate, sesame seeds, nuts, calamari, lobster and many other foods!
Penny Experiment
If I ask you what a penny is made of, you would probably say copper. This is correct, but it's not the only thing that pennies are made of! Try this:

1. Collect a lot of pennies from different years, and a strong magnet

2. Line up the pennies in a line according to the year they have on them

3. You will probably notice that the really old pennies don't stick to the magnet. This is because the price of copper used to be a lot lower so we used to make our pennies entirely out of copper. Copper isn't magnetic

4. You will also notice that the recently made pennies also don't stick to the magnet. Because copper is now quite expensive, we've started to make our pennies out of zinc with a copper coating. They will feel a lot lighter than the pure copper pennies because zinc weighs less than copper. Zinc is also not magnetic

5. But all the other pennies should stick to the magnet! We used to make pennies out of steel with a copper coating. And steel is magnetic!

Pretty cool eh?

Pyrite

Pyrite is also known as "Fool's Gold". It is a very pretty mineral and usually forms interesting crystals.

The word "Pyrite" comes from the Greek words pyrites lithos, meaning "stone which strikes fire". They discovered that when you hit pyrite with iron it would spark. This is why it was used to start fires!

Pyrite was also polished by Native Americans in early times and used as a mirror!

At the University of Waterloo's Earth Science Museum we have a display dedicated to the different crystals of pyrite.
Used in:

Jewelry (Called Marcasite)

Pyrite sparks when you hit it with steel, so it was used in early rifles

Used in the manufacturing of paper and ink

Gypsum

Gypsum forms deep under water when creatures like clams, oysters, scallops and other shellfish die. Their remains settle to the ocean floor in layers. Over time, hundreds of layers form and push down from on top of the original layer. This causes it to be turned into rock. Some of this rock contains gypsum.

Gypsum is a very soft mineral. It can be scratched with your finger nail!
Used in:

Manufacture of Wallboard

Cement

Plaster

Fertilizer

Used to make medical casts (they put this on you when you break a bone!)

Quartz

Quartz is one of the most abundant minerals on the planet. It comes in a lot of different colours such as pink (rose quartz), yellow (citrine), purple (amethyst), white (milky quartz), red (amethyst with hematite), and brown and grey (smoky quartz). When we want quartz today we often make it in a furnace instead of digging it out of the ground.

Quartz is used in watches! A battery powers a microchip, which sends messages to a quartz crystal, causing it to vibrate 32,768 times a second. Every time the quartz vibrates that exact number, it sends a message to a motor which turns the hands on your watch!

Quartz has been found on the moon!
Used in:

Watches

Gemstones

A source of silica for glass

Electrical components

Optical lenses

Sandpaper

Calcite

Calcite is a very common mineral found in most places on earth. Calcite comes in over 300 different shapes, this is more than any other mineral. Pure calcite is colourless or white, but due to impurities it may also be red, yellow, green, honey, pink, lavender, black, brown or blue.

An interesting way of identifying calcite is the acid test. When you place a drop of weak acid, such as vinegar, on calcite it will bubble!
Used in:

Concrete and asphalt

Making medicines, such as antacid tablets (chewable tums)

Fed to chickens

Buildings

Sodalite

Sodalite is a vibrantly blue mineral which was named for its high sodium content (sodium is in table salt!) It has a greasy lustre, which means that if you can get a good look at a clean crystal then it will look like the surface of the mineral is greasy.

Sodalite is a highly fluorescent mineral. This means that if you have an ultraviolet light (a black light/ the light that is used for glow-in-the-dark mini putt) and you shine the light on a piece of sodalite then it will glow!
Use​d in:
Mica

Different forms of mica have different names. For example, white mica is muscovite, while black mica is biotite. No matter what the colour, the properties of this mineral group are similar. It is very flexible, you can bend it in one direction and when you let go it will return to its original shape. It is also very soft and you can scratch the surface of mica with your fingernail. Crystals form with really strong bonds in one direction, and really weak bonds in another direction. Because of this, the crystal can be broken apart in sheets!
Used in:

toasters

Sparkles in cosmetics

Old stove windows

Makes your camera flash

Labradorite

Labradorite was first discovered in 1770. It was named after Newfoundland and Labrador in Canada, but it is also found in other areas of the world. Labradorite is a type of feldspar (the most abundant mineral family) with stunning colours and visual effects. Its colours can range between violet, blue, green, yellow and even orange-red. These colours are only viewed when rotated at an angle and appears through the entire surface of the stone.
Used in:
Magnetite

Magnetite is a magnetic rock. In fact, it is the most magnetic mineral on earth. Naturally magnetized pieces of magnetite are called lodestone. It is black and shiny.

There's a piece of magnetite in the Peter Russell Rock Garden. Bring a magnet with you the next time you visit and try to figure out which rock it is! Magnetite image source
Used in:

Early compasses

An ore or iron

Pigment in paints

In fertillizers

Want to find your own magnetite? It's simple! All you need to do is run a magnet through sand. You should find that little tiny grains of black sand sticks to the magnet, while all other sand doesn't. What you're collecting is tiny grains of magnetite! Don't forget to put it into a plastic bag so that you don't lose it!

Magnetite fillings image source.

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Minerals for Kids | Earth Sciences Museum

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Click on a Mineral name to learn more about it! Fluorite Gypsum Sodalite Magnetite Copper Quartz Mica Pyrite Calcite Labradorite Fluorite is really interesting!

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Minerals in Your House | Mineralogy4Kids

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Minerals in Your House Home Minerals in Your House [...]

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Are You a Rockhound or "Just" a Mineral Collector?
Check to see how many of the following signs apply to you, if it's over 10, then watch out! You're a ROCKHOUND!
(modified from Rockhounds.com)

Rocks and Soils
At this site you can play an interactive game with Sara Jane to save the world, read about the characteristics of rocks, their uses, and learn about soils and take a quiz to see how much you've learned.
(from the BBC)
Making a Silica Tetrahedron from a Small Envelope
(from the NM Bureau of Geology & Mineral Resources)

The coloring book was designed by Melanie Sanderson and adapted from the Sammy Soil story by Ernest H. Whitaker and Sandra L. Purdue. Natural Resources.
(from the Gulf of Mexico Program)
Investigating Symmetry In Our Alphabet
Minerals Down Under
Learn all about the physical properties of gold, copper, silver, iron, and mineral sands along with the techniques used to find them. Finish up with a quiz to check how much you learned.
(from the Minerals Council of Australia)

Learn about rocks while creating a rock collection then test your new skills.

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Mineral Games Home Mineral Games Mineral Games Are [...]

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A mineral is a naturally-occurring, inorganic solid which possesses a characteristic internal atomic structure and a definite chemical composition.

If we take the definition of a mineral term by term, it becomes easier to understand:

Minerals must occur naturally. This means man-made substances such as steel aren't minerals.

Inorganic substances are those substances that are not living and are not formed by living processes.

Crystalline solids are those solids in which the atoms composing the solid have an orderly, repeated pattern.

Minerals will have definite chemical compositions, but these compositions may vary within given limits.

Substances that have these features will also have distinctive physical properties such as color, crystal form, cleavage, luster, streak, etc.

You can find out more about minerals by clicking on the buttons on the right.

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A mineral is a naturally-occurring, inorganic solid which possesses a characteristic internal atomic structure and a definite chemical composition. If we take the definition of a mineral term by term, it becomes easier to understand: Minerals must occur naturally. This means man-made substances such as steel aren't minerals.

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A mineral can be defined as an inorganic substance that occurs naturally in the earth 's crust and can be represented by a chemical formula. These substances are an important part of our everyday life. Minerals are generally solid at room temperature and have a crystal structure because its atoms have a definite arrangement. More than 3,000 different minerals have been found. There are two different types of minerals which are metallic minerals and non-metallic minerals. Iron ore is an example of metallic minerals and limestone is an example of non-metallic minerals.
Quick Facts: -

The hardest mineral in the entire world is the diamond. It is made up of just carbon.

Quartz is the most common type of mineral found on the earth. It contains two oxygen atoms for every silicon atom.

Large mineral crystals are produced when magma cools at a slow rate and small crystals are produced when magma cools at a fast rate.

Approximately 60% of the earth's crust is covered by the mineral feldspar. This mineral is used to make ceramics.

There are 16 different minerals that are required in our diet. The human body requires minerals different from the ones found in nature.

Our body needs the elements found within the minerals.

Ruby and Sapphire are formed of a mineral called corundum that comprises of aluminum oxide.

Plagioclase belongs to the same mineral family as feldspar. It is used to identify the origin of igneous rocks.

The ability of minerals to scratch each other is measured by the Mohs scale of hardness.

Approximately 30 types of minerals are commonly found in the earth's crust.

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More than 3,000 different minerals have been found. There are two different types of minerals which are metallic minerals and non-metallic minerals.

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So many things we use every day came from rocks and minerals. Can you figure out where glass, pencils, foil, and coins originated?

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Rocks and Minerals | Kids Discover Online

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Properties of Minerals | Earth Science | Visionlearning

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Minerals are classified on the basis of their chemical composition, which is expressed in their physical properties. This module, the second in a series on minerals, describes the physical properties that are commonly used to identify minerals. These include color, crystal form, hardness, density, luster, and cleavage.

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Minerals can be identified using a number of properties. These include physical and chemical properties such as hardness, density, cleavage and colour, crystallography, electrical conductivity, magnetism, radioactivity and fluorescence.

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Minerals can be identified using a number of properties. These include physical and chemical properties such as hardness, density, cleavage and colour, crystallography, electrical conductivity, magnetism, radioactivity and fluorescence.

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Minerals | Types and Properties of Minerals | Video for Kids

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What are Minerals?

All rocks except obsidian and coal are made of minerals. (Obsidian is a volcanic rock made of glass and coal is made of organic carbon.) Most rocks contain several minerals in a mixture characteristic of the particular rock type. When identifying a rock you must first identify the individual minerals that make up that rock.

Minerals are naturally occurring, inorganic solids with a definite chemical composition and a crystal lattice structure. Although thousands of minerals in the earth have been identified, just ten minerals make up most of the volume of the earth's crust-plagioclase, quartz, orthoclase, amphibole, pyroxene, olivine, calcite, biotite, garnet, and clay.

Together, the chemical formula (the types and proportions of the chemical elements) and the crystal lattice (the geometry of how the atoms are arranged and bonded together) determine the physical properties of minerals.

The chemical formula and crystal lattice of a mineral can only be determined in a laboratory, but by examining a mineral and determining several of its physical properties, you can identify the mineral. First, you need to become familiar with the physical properties of minerals and how to recognize them.

Minerals can be identified by their physical characteristics. The physical properties of minerals are related to their chemical composition and bonding. Some characteristics, such as a mineral's hardness, are more useful for mineral identification. Color is readily observable and certainly obvious, but it is usually less reliable than other physical properties.

How are Minerals Identified?

Mineralogists are scientists who study minerals. One of the things mineralogists must do is identify and categorize minerals. While a mineralogist might use a high-powered microscope to identify some minerals, most are recognizable using physical properties.

Check out the mineral in figure 1. What is the mineral's color? What is its shape? Are the individual crystals shiny or dull? Are there lines (striations) running across the minerals?

Color, Streak, and Luster

Diamonds are popular gemstones because the way they reflect light makes them very sparkly. Turquoise is prized for its striking greenish-blue color. Notice that specific terms are being used to describe the appearance of minerals.

Color

Color is often useful, but should not be relied upon. Different minerals may be the same color. Real gold, as seen in figure 2, is very similar in color to the pyrite in figure 1.

Additionally, Some minerals come in many different colors. Quartz, for example, may be clear, white, gray, brown, yellow, pink, red, or orange. So color can help, but do not rely on color as the determining property. Figure 3 shows one sample of quartz that is colorless and another quartz that is purple. A tiny amount of iron makes the quartz purple. Many minerals are colored by chemical impurities.

Luster

Luster describes the reflection of light off a mineral's surface. Mineralogists have special terms to describe luster. One simple way to classify luster is based on whether the mineral is metallic or non-metallic. Minerals that are opaque and shiny, such as pyrite, have a metallic luster. Minerals such as quartz have a non-metallic luster.

Luster is how the surface of a mineral reflects light. It is not the same thing as color, so it is crucial to distinguish luster from color. For example, a mineral described as "shiny yellow" is being described in terms of luster ("shiny") and color ("yellow"), which are two different physical properties. Standard names for luster include metallic, glassy, pearly, silky, greasy, and dull. It is often useful to first determine if a mineral has a metallic luster. A metallic luster means shiny like polished metal. For example cleaned polished pieces of chrome, steel, titanium, copper, and brass all exhibit metallic luster as do many other minerals. Of the nonmetallic lusters, glassy is the most common and means the surface of the mineral reflects light like glass. Pearly luster is important in identifying the feldspars, which are the most common type of mineral. Pearly luster refers to a subtle iridescence or color play in the reflected light, same way pearls reflect light. Silky means reflecting light with a silk-like sheen. Greasy luster looks similar to the luster of solidified bacon grease. Minerals with dull luster reflect very little light. Identifying luster takes a little practice. Remember to distinguish luster from color.

Different types of non-metallic luster are described in table 1.

Can you match the minerals in figure 4 with the correct luster from table 1?

Streak

Streak is the color of a mineral's powder. Streak is a more reliable property than color because streak does not vary. Minerals that are the same color may have a different colored streak. Many minerals, such as the quartz in the figure 3, do not have streak.

To check streak, scrape the mineral across an unglazed porcelain plate (Figure 5). Yellow-gold pyrite has a blackish streak, another indicator that pyrite is not gold, which has a golden yellow streak.

Specific Gravity

Density describes how much matter is in a certain amount of space: density = mass/volume.

Mass is a measure of the amount of matter in an object. The amount of space an object takes up is described by its volume. The density of an object depends on its mass and its volume. For example, the water in a drinking glass has the same density as the water in the same volume of a swimming pool.

The specific gravity of a substance compares its density to that of water. Substances that are more dense have higher specific gravity.

Hardness

Hardness is the strength with which a mineral resists its surface being scraped or punctured. In working with hand samples without specialized tools, mineral hardness is specified by the Mohs hardness scale. The Mohs hardness scale is based on 10 reference minerals, from talc the softest (Mohs hardness of 1), to diamond the hardest (Mohs hardness of 10). It is a relative, or nonlinear, scale. A hardness of 2.5 simply means that the mineral is harder than gypsum (Mohs hardness of 2) and softer than calcite (Mohs hardness of 3). To compare the hardness of two minerals see which mineral scratches the surface of the other.

With a Mohs scale, anyone can test an unknown mineral for its hardness. Imagine you have an unknown mineral. You find that it can scratch fluorite or even feldspar, but apatite scratches it. You know then that the mineral's hardness is between 5 and 6. Note that no other mineral can scratch diamond.

Cleavage and Fracture

Breaking a mineral breaks its chemical bonds. Since some bonds are weaker than other bonds, each type of mineral is likely to break where the bonds between the atoms are weaker. For that reason, minerals break apart in characteristic ways.

Cleavage

Cleavage is the tendency of a mineral to break along certain planes to make smooth surfaces. Halite breaks between layers of sodium and chlorine to form cubes with smooth surfaces (figure 6).

A mineral that naturally breaks into perfectly flat surfaces is exhibiting cleavage. Not all minerals have cleavage. A cleavage represents a direction of weakness in the crystal lattice. Cleavage surfaces can be distinguished by how they consistently reflect light, as if polished, smooth, and even. The cleavage properties of a mineral are described in terms of the number of cleavages and, if more than one cleavage, the angles between the cleavages. The number of cleavages is the number or directions in which the mineral cleaves. A mineral may exhibit 100 cleavage surfaces parallel to each other. Those represent a single cleavage because the surfaces are all oriented in the same direction. The possible number of cleavages a mineral may have are 1,2,3,4, or 6. If more than 1 cleavage is present, and a device for measuring angles is not available, simply state whether the cleavages intersect at 90° or not 90°.

To see mineral cleavage, hold the mineral up beneath a strong light and move it around, move it around some more, to see how the different sides reflect light. A cleavage direction will show up as a smooth, shiny, evenly bright sheen of light reflected by one set of parallel surfaces on the mineral.

Mica has cleavage in one direction and forms sheets (figure 7).

Minerals can cleave into polygons. Fluorite forms octahedrons (figure 8).

One reason gemstones are beautiful is that the cleavage planes make an attractive crystal shape with smooth faces.

Fracture

Fracture is a break in a mineral that is not along a cleavage plane. Fracture is not always the same in the same mineral because fracture is not determined by the structure of the mineral.

Minerals may have characteristic fractures (figure 9). Metals usually fracture into jagged edges. If a mineral splinters like wood, it may be fibrous. Some minerals, such as quartz, form smooth curved surfaces when they fracture.

All minerals have fractures. Fracture is breakage, which occurs in directions that are not cleavage directions. Some minerals, such as quartz, have no cleavage whatsoever. When a mineral with no cleavage is broken apart by a hammer, it fractures in all directions. Quartz is said to exhibit conchoidal fracture. Conchoidal fracture is the way a thick piece of glass breaks with concentric, curving ridges on the broken surfaces. However, some quartz crystals have so many flaws that instead of exhibiting conchoidal fracture they simply exhibit irregular fracture. Irregular fracture is a standard term for fractures that do not exhibit any of the qualities of the other fracture types. In introductory geology, the key fracture types to remember are irregular, which most minerals exhibit, and conchoidal, seen in quartz.

Crystal Shape

All minerals are crystalline, but only some have the opportunity to exhibit the shapes of their crystals, their crystal forms. Many minerals in an introductory geology lab do not exhibit their crystal form. If a mineral has space while it grows, it may form natural crystals, with a crystal shape reflecting the geometry of the mineral's internal crystal lattice. The shape of a crystal follows the symmetry of its crystal lattice. Quartz, for instance, forms six-sided crystals, showing the hexagonal symmetry of its crystal lattice. There are two complicating factors to remember here: (1) minerals do not always form nice crystals when they grow, and (2) a crystal face is different from a cleavage surface. A crystal face forms during the growth of the mineral. A cleavage surface is formed when the mineral is broken.

Other Identifying Characteristics

There are some properties that only help to distinguish a small number of minerals, or even just a single mineral. An example of such a special property is the effervescent reaction of calcite to a weak solution of hydrochloric acid (5% HCl). Calcite fizzes or effervesces as the HCl solution dissolves it and creates CO ₂ gas. Calcite is easy to identify even without testing the reaction to HCl, by its hardness, luster and cleavage.

Another special property is magnetism. This can be tested by seeing if a small magnet responds to the mineral. The most common mineral that is strongly magnetic is the mineral magnetite. A special property that shows up in some samples of plagioclase feldspar is its tendency to exhibit striations on cleavage surfaces. Striations are perfectly straight, fine, parallel lines. Magnification may be required to see striations on plagioclase cleavage surfaces. Other special properties may be encountered on a mineral-to-mineral basis.

Some minerals have other unique properties, some of which are listed in table 3. Can you name a unique property that would allow you to instantly identify a mineral that's been described quite a bit in this chapter? (Hint: It is most likely found on your dinner table.)

Table 3. Some minerals have unusual properties that can be used for identification.

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All rocks except obsidian and coal are made of minerals. (Obsidian is a volcanic rock made of glass and coal is made of organic carbon.) Most rocks contain several minerals in a mixture characteristic of the particular rock type. When identifying a rock you must first identify the individual minerals that make up that rock.

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Identifying Rocks and Minerals - Earth Science for Kids!

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Learn about precious and semi-precious gems.

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National Geographics | Rocks And Minerals Read-Aloud

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OneGeology - Education - OneGeology Kids - Rocks and minerals