10 Essential Specimens for Every Awesome Mineral Collection

10 Essential Specimens for Every Awesome Mineral Collection

Minerals are the building blocks of every rock in our world. Some minerals are so common that they form all over the world and others are so rare that you can only find them in a few places on Earth. We’ve compiled a list of our top 10 favorite samples for every mineral collection. Whether you collect for fun or teach science classes or homeschool your children, this list is a must.

Quartz

Quartz with Amethyst

Quartz with Amethyst

Quartz is a very common mineral that has many variations. The classic quartz samples are colorless with a hexagonal shape which looks like two hexagonal pyramids with a hexagonal barrel in between. Quartz has a hardness of 7 on the Mohs Scale of Hardness, a white streak, conchoidal fracture (no cleavage), and glassy luster. Nice samples of quartz can be found worldwide in geodes, Alpine fissures and often in the igneous rock pegmatite. Quartz has many uses including prisms, lenses, gauges, glass, paint, and abrasives. There are numbers varieties of quartz including but not limited to:

Herkimer Diamond: Clear variety with perfect shape

Rose Quartz

Rose Quartz

 

Amethyst: Purple variety

Citrine: Brownish-Orange variety

Rose Quartz: Pink variety

Milky Quartz: White variety (opaque)

Carnelian: Orange Cryptocrystalline variety

Oco Eggs: Agate geodes often with crystal centers

Chalcedony: Cryptocrystalline variety forms in many colors and often banded

Jasper: Cryptocrystalline variety that forms in many colors such as red, yellow, brown, black, gray and white

Why you need it: Quartz is one of the main building blocks of many of Earth’s rocks. With the amazing number of varieties, you can find multiple samples that span a wide range of colors and sizes. Being able to identify quartz will help you identify many rock types.

 

Calcite

Calcite

Calcite

Calcite is another common mineral that forms many varieties of sedimentary rocks all over the world. Calcite comes in many colors such as colorless, gray, red, yellow, green, blue, violet, brown, or black. This awesome mineral is soft, being only a 3 on the Mohs Scale of Hardness. Calcite has a white streak, glassy to pearly luster, rhombic cleavage.  This mineral is useful in the production of microscopes, building materials, and fertilizers, and as a component in the chemical industry and metallurgy. Calcite often forms in water-rich environments or in caves.

Iceland Spar Calcite: A clear variety that has optical properties. Place a piece over text or an image and it will appear doubled through the crystal.

Why you need it: Calcite is made of calcium carbonate which will react (fizz or bubble) in the presence of an acid. This property is useful in identifying the mineral and rocks that contain calcite like limestone or marble. Calcite reacts easily with strong acids such as hydrochloric but will also react with weaker acids like lemon juice or vinegar, especially on a fresh surface.

 

Gypsum

Gypsum

Gypsum

Selenite Stick

Selenite

 

Gypsum is an evaporate mineral that often forms due to the evaporation of lakes or oceans. Gypsum is often white or pinkish-white, very soft being a 2 on the Mohs Scale of Hardness, has as a glassy to silky to pearly luster, cleavage in one direction, and a white streak. Gypsum has many uses including paints, tile, drywall, blackboard chalk, fertilizer, and Plaster of Paris. Wonderful samples of gypsum are found in Mexico, Italy, Russia, France, Canada and the United States. Gypsum will dissolve in water over time.

Gypsum Rose

Gypsum Rose

 

Selenite Gypsum: A fibrous variety which forms long white sticks of crystal clusters.

Gypsum Roses: A unique form of gypsum where the crystals grow is a rose-shaped cluster.

Why you need it: Gypsum is one of the softest minerals on the Mohs scale. This is a great sample to use when learning to test mineral identities. The unique forms of gypsum roses and selenite sticks make fun additions to any collection.

 

Halite

Halite

Halite

Halite is the mineral table salt. This mineral forms as an evaporate mineral when sea beds dry. Halite often forms in wide, thick layers in colors ranging from colorless to white, yellow, red, brown, light blue, dark blue, violet, and pink. With a hardness of 2.5 on the Mohs scale, it is slightly harder than gypsum, has a white streak, glassy luster and cubic cleavage. Nice specimens of halite are located in Germany, Poland, Spain, Austria, United States, and Italy. Halite is primarily used for food preparation and in the chemical industry.

Why you need it: Halite is used in everyday activities and is a great example of how natural Earth minerals are used in our lives. Also, halite’s cubic cleavage allows the samples to break into perfect cubes each time you break a sample.

 

Magnetite

Magnetite

Magnetite

Magnetite is a black mineral with moderate hardness, 5.5 to 6.5 hardness on Mohs Scale of Hardness, metallic streak and very heavy. This common mineral is present in many rock types and has a high iron content. Nice samples often occur in Sweden, Austria, United States, Italy, Switzerland, South Africa, and Russia.

Why you need it: Magnetite is magnetic and can be picked up by a magnet and can also pick up smaller items like metal paperclips.

 

Hematite

Hematite

Hematite

A Mini Me Geology favorite, hematite is typically gray to black in color, has a metallic to earthy luster, and is a 5 to 6 on the Mohs Scale of Hardness. Hematite is a heavy mineral that is found worldwide. It’s presence in a rock will cause it to have a reddish color. Hematite is useful for its iron content, red pigments, jewelry and in plate-glass.

Why you need it: Hematite is a great mineral for teaching streak and hardness to students because while the outer mineral color is gray to black, the streak color is cherry red.

 

Green Fluorite

Green Fluorite

Fluorite

Blue John Fluorite

Blue John Fluorite

Fluorite is a unique mineral in that it can be almost any color other than black. Common colors are green, purple, white, yellow, blue and red. Fluorite is a 4 on the Mohs Scale of Hardness, has a white streak, and glassy luster. Found worldwide, nice samples of fluorite are located in Germany, Italy, Switzerland, and Mexico. A rare type of striped fluorite, the Blue John Fluorite, it located in caverns in the Castleton, Derbyshire, England area. Fluorite is often found in veins of rock and is used in enamels, cooking utensils, telescopes, and camera lenses.

Why you need it: Fluorite is a colorful mineral that can form in cubes but can also be broken into octahedrons.

 

Kyanite Blade

Kyanite Blade

Kyanite

Kyanite is a unique light blue, blue-gray or black mineral that forms in blades.  The hardness of the mineral is 4 to 5 on the Mohs Scale along the blades and 6 to 7 across the blade. The mineral has a white streak, glassy to pearly luster and is useful in the production of ceramic products, electrical insulators, and abrasives. Kyanite is often found in metamorphic rocks like schist and gneiss. Nice samples are present in Switzerland, Italy, Austria, France, Kenya, Brazil, and the United States.

Why you need it: The difference in the hardness across two directions of the blades is a unique feature. Kyanite is also a key metamorphic mineral which helps identify certain samples.

 

Muscovite Mica

Muscovite Mica

Mica

Mica is one of the most interesting minerals because it forms in stacks of super thin sheets along a single cleavage plane (basal cleavage). These stacks are called “books.” Mica forms in colors of black, brown, rose, silver, yellow, gray, purple or dark green and is very soft being only a 2.5 to 3 on the Mohs Scale of Hardness. A colorless streak and a glassy to pearly luster are also characteristic of this mineral. Nice specimens of mica are located in the United State, Italy, Russia, Brazil Madagascar, Australia, Germany, Canada, Japan, and Greenland although it occurs in rocks around the world. Mica is popular mineral for collecting and rock identification. Mica is a prominent component of pegmatite igneous rocks.

Three notable varieties of mica are the black Biotite, silver Muscovite, and purple Lepidolite.

Why you need it:  Mica is a fun mineral to collect and is a great example of unique properties when teaching students. You can peel individual layers of books apart with your fingernails. Mica sheets are also very flexible, which is not common in many other minerals.

 

Microcline Feldspar

Microcline Feldspar

Feldspar

Feldspar is a common mineral in many rock types such a granitic pegmatite igneous rocks and a variety of metamorphic rocks. Feldspars are often white, pink or green, have a moderate hardness of 6 to 6.5 on the Mohs Scale, a glassy luster, and two intersection cleavage planes. Nice samples occur worldwide and are popular for collectors and scientists as a means of sample identification. Some feldspars are also popular in the production of jewelry.

Why you need it: The feldspar minerals make up over half of the Earth’s crust. Plagioclase feldspar varieties exhibit unique striations (fine lines) on their crystal face.

Do you have other minerals that you would add to the list? Let us know what you would collect and why!

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