Mini Me Geology Blog

Whether it is Christmas, Hanukkah, birthday or another special event, finding the perfect gift is part of the excitement. We know you want to give a great gift that is fun and unique. As parents, we often want gifts that are also “good” for children because they are healthy, engaging, or educational. For the adults on our list, we are always searching for something new and different that will be a happy surprise. Mini Me Geology has the perfect mix of ideas for everyone on your list from your youngest rockhound, to the teenagers in your life, and adult friends and family who love collecting beautiful samples and crystals for spiritual well-being.

Best Science Gifts for Toddler Rockhounds

Kids under six years old are curious when it comes to science and educational toys but they are still at an age where small parts in some science kits might be a choking hazard if the kids are left unattended. That is why we created the Rock & Mineral Coloring & Activity Book for kids! This fun book is loaded with 78 pages of childhood fun including Drawing Pages, Coloring Pages, Roc-Tac-Toe, Foursquare, Word Scrambles, Crossword Puzzles, Word Finds, Mazes, Creative Writing Stories, and Make-a-Word Games. The Rock & Mineral Coloring & Activity Book was designed with fun activities that also help children become interested in science.

The Best Science Gift for 6 to 12-Year-Olds

Kids that are 6 to 12-year-olds are the perfect age for beginning science kits. In fact, the child who inspired the launch of Mini Me Geology was six years old when he first covered the wonder of rocks and minerals. As a mother and geologist, the owner of Mini Me Geology set out specifically to design kits for this age group so that kids could learn about rocks and minerals but also explore through fun activities such as experiments, puzzles, mazes, coloring pages, writing activities, and creative crafts.

Be a Rock Detective!

The Rock Detectives line of kits is specifically designed for the 6 to 12-year-old age group. There are six kits in the series, each with its own detective’s theme. The kits include Mineral Mission, Crystal Experiments, Crystal Geometry, Metamorphic Mystery, Sedimentary Sleuthing, and Igneous Investigation.

Each of these kits has six or seven samples that were specifically picked to fit the theme and a hand magnifier for viewing the samples up close. Each kit has a 30-page PDF eBook that is included on a CD. If you don’t have a CD player that is no problem! We have download links for all of the eBooks and you are able to print as many copies as you like for all the kids in your household. The best part of these kits is that we designed them so that the kids can work on some of the activities alone and perform others with their parents, teachers, and groups just like real scientists!

Junior Rock & Mineral Kits for Kids

The My Rockin’ Collection Junior kits series is a favorite for kids between the ages of 6 and 12. Housed in sleek tubes, the junior kits are easy to store between uses, which keeps the rocks off the floor and safe. The My Rockin’ Collection Junior kits are one of our best-selling lines because kids can explore the samples on their own or with a parent. There are four kits in this collection including Minerals, Igneous Rocks, Sedimentary Rocks, and Metamorphic Rocks. Each kit has 10 of the most popular samples from the category and an identification poster that includes fun information, identification tips, and pictures of each of the rocks to help your kids identify all of the samples in the collection.

The Best Science Gifts for Teens and Young Adults

Older kids who are interested in science really love the idea of experimenting with the samples. We designed several collections and kits that allow them to do just that.

Explore the Rock Cycle

The Rock Cycle Kit is one of our most popular kits for teens. This fantastic kit has 20 rock and mineral samples, a hand magnifier for examining the specimens, and a PDF eBook full of information about each of the samples, the rock cycle and how it works throughout the Earth, plus activities, experiments, and games. The Rock Cycle Kit is great for kids who are interested in becoming a scientist because the activities of the kit help them develop a fascination with science and the critical thinking skills with a need for any type of science in the future.

Testing and Experiment Kits

Our most popular kit for teens is the Mineral Observation, Hardness, and Streak Testing Kit. This kit is based on the Mohs Scale of Mineral Hardness and includes eight samples from the scale, identification accessories including a white streak plate, a black streak plate, and information cards that explain how to use all of the identification tools.

Popular Science Gifts for Kids of Any Age

Many of the kits we design can cross age groups and uses. We love helping kids explore science at home and helping teachers and homeschool parents in the classroom.

Mineral Madness Kit

Mineral Madness is our newest kit for kids and teens. This fun kit has 15 minerals, a white streak plate, and an information brochure with pictures and details about each of the samples, their properties, and fun facts so your kids learn to identify the samples and recognize them in nature.

Earth’s Treasures Geology Sifting Cups

A favorite of gift-givers and birthday parties, the Earth’s Treasures Geology Sifting Cups are filled with real beach sand, rocks, minerals, and fossils. As kids sift the sand, they find their treasures. Each Earth’s Treasures Geology Sifting Cup is slightly different making them fun to collect and the perfect party favor.

Crack-Your-Own Geodes

Crack Your Own Geodes are a fan favorite for all ages (adults, too). We carry only the largest geodes available that are filled with beautiful quartz crystals. You will love to see the excitement on your kids’ faces as they crack open the rocks to reveal the shimmering quartz crystals inside.

The Colossal Rock & Mineral Kit

Our largest kit is perfect for ages six through adult. The Colossal Rock & Mineral Kit is a two-box kit that includes 10 samples each of minerals, igneous rocks, sedimentary rocks and metamorphic for a total of 40 samples. White and black streak plates, a hand magnifier and four identification posters are also included in the kit. Kids will learn about the color, streak, crystal shape, hardness, luster, special features, common locations and uses of minerals while discovering and the different colors, textures, mineral content, uses and properties of rocks as you observe and test your new samples. The colossal rock and mineral kit is house in plastic storage boxes which helps keep everything organized and neat. This is the perfect science gift for future scientists and engineers!

Best Gifts for Adult Rock Collectors

Many adults enjoy collecting unique and interesting rock and mineral samples. Mini Me Geology strives to find the best samples available for our customers. Our collection includes over 120 rocks and minerals so you have an amazing selection to choose from. Each sample comes with an information card that details the properties of the sample, common uses, specials features, and popular collection locations.

Best Gifts for Everyone Who Loves Healing Crystals

Using crystals in meditation and healing practices is very popular today. We have curated a wonderful selection of rough, natural minerals and crystals that pair with each of the body’s chakras so you can create your own personalized collection. If you prefer a pre-made kit, the Natural Chakra Crystals kit has eight wonderful crystals that include one for each chakra and quartz to amplify the power of the others. The included information brochure provides details about each sample and the related chakra and pictures of the crystals for easy identification.

Science gifts are perfect for everyone on your list because they are fun, exciting, and unique. If you have questions about specific kits and samples, contact us and we will be happy to help.

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Filed under: Geology / Earth Science on December 8th, 2019 | Comments Off on The Best Sciences Gifts for Everyone on Your List

Gypsum is one of the most unique minerals found in the world with beautiful samples forming in numerous countries and settings. Some minerals, like gypsum, have the fascinating ability to take on different shapes depending on the environment where they grow.

The name Gypsum comes from the Greek word gypsos, which means plaster and mentions of the minerals are known beginning approximately 300 BC. Around the globe, gypsum forms in massive chunks, clear crystals, and as fibrous bundles. Gypsum is a soft mineral and was chosen as an example mineral by Friedrich Mohs for this Scale of Mineral Hardness.

Physical and Chemical Properties of Gypsum

Gypsum is a soft, evaporite mineral that you can easily scratch with your fingernail. Because of its unique properties, gypsum is great for school projects and in-class experiments. Here are some of gypsum’s interesting physical and chemical properties.

• Chemical Formula: CaSO₄  2H₂O
• Color:   Colorless to white but may appear with shades of pink, tan, yellow, blue, brown, red and gray from the presence of impurities in the mineral.
• Hardness:                 2 on Mohs Hardness Scale.
• Streak:                     White
• Luster:                      Glassy, Silky, Pearly, or Waxy
• Cleavage:                 Perfect
• Fracture:                   Splintery or Conchoidal
• Specific Gravity:       2.312 – 2.322
• Crystal System:        Monoclinic
• Crystal Shape:          Thick tabular to lenticular crystals. At times, maybe prismatic. Varieties can for rosette clusters, granular masses, and fibrous masses.

Varieties and Forms of Gypsum

Gypsum is very common throughout the world and has many varieties that can form as single crystals or clusters of many crystals in varying shapes. Massive Gypsum is a common variety that many people think of when they hear of the mineral.

Gypsum is also known to form “roses” which are clusters of lenticular (lens-shaped) crystals. Alabaster is a fine-grained massive form of the mineral that is typically white in color. Due to its beautiful hue and softness, alabaster is a favorite sculpture medium for artists.

Selenite is a clear, crystal form of gypsum. Clear selenite often has good cleavage planes and a pearly luster. Selenite was named after the Greek word for moon because of the “moonlight” appearance when light reflects off of the crystal surface.

Satin Spar is a white, fibrous form of selenite which forms in long strands, which grouped together, form “sticks.” Satin Spar selenite appears and feels silky.

Uses of Gypsum Minerals

Gypsum is one of the most useful minerals on earth. From ancient times to now, people have found ways to use gypsum in a variety of products including:

• Paint
• Tile
• Drywall
• Blackboard Chalk
• Fertilizer
• Plaster of Paris
• Food
• Hair Products
• Skin Cream
• Environmental Restoration
• Dentistry Impressions
• Sculpture (Blocks of Alabaster)
• Metaphysical practices (selenite variety typically)

9 Gypsum Mineral Fun Facts

1. Gypsum is the most common mineral on earth containing sulfur.
2. Gypsum can form very large crystals, the largest known being 39 feet long found in the Cave of the Crystals in Naica, Chihuahua, Mexico.
3. Gypsum often forms in sedimentary environments like lakes and oceans when the water evaporates leaving the mineral behind.
4. Gypsum will slowly dissolve in cold water.
5. Gypsum has water in its crystal structure. When the mineral is heated, it will lose the water and transform into bassanite (plaster) and then anhydrite.
6. Because Gypsum is very soft and has perfect cleavage, it is very difficult to cut gypsum with facets. This is why gypsum jewelry is not common.
7. White Sands National Monument in New Mexico is made of rare gypsum sand. Gypsum typically dissolves in water rather than breaking down into sand particles, which is why the White Sand National Monument is so special.
8. Gypsum often forms with other minerals like halite (table salt), sulfur, calcite, quartz, pyrite, dolomite, fluorite, and azurite.
9. A sample of gypsum will fluoresce with colors of light blue, yellow and golden yellow under a UV light.

Locations of Gypsum Minerals

Gypsum is found all over the world. Some of the largest and most interesting deposits are located in Mexico, Brazil, Italy, Russia, France, Canada, and the United States.

Explore Gypsum and Add to Your Collection

Mini Me Geology has fabulous samples of gypsum and satin spar selenite available as individual samples and in kits. These great samples are perfect for conducting experiments and adding to a growing collection. Gypsum samples are included in our: My Rockin’ Collection Deluxe Kit, the Junior My Rockin’ Collection Kit, the Colossal Rock and Mineral Kit, Mineral Madness, and the Mineral Observation, Hardness & Streak Testing Kit. If you have any quesitons about gypsum or any of our awesome samples, let us know!

Filed under: Geology / Earth Science on August 28th, 2019 | Comments Off on Rocks and Minerals We Love: GYPSUM MINERALS

Is your little one having a birthday? Do they love rocks and minerals? Then throw them a Rock Detectives Geology Birthday Party!  This party idea is based on Mini Me Geology’s Rock Detectives line of kits to give your child and their guests hours of fun.

Below you will find a Rock Detectives Geology Birthday Party Plan with ideas that will help you design a party full of rock and mineral identification activities, geode cracking, panning for minerals, and storage box creation. Throwing a party is simple, choose the Rock Detectives kits that you want to use as the theme for the party such as minerals, crystals, rocks, or all of them.  Your kids can learn about Metamorphic Mysteries, become a Sedimentary Sleuth or solve an Igneous Investigation. You can also design your party around our Crystal Geometry and Crystal Experiments kits or go on a Mineral Mission.

Our Rock Detectives Birthday Party Invitations and Activities eBook includes instructions for panning, geode cracking, storage box creation, and rock bingo as well as invitations to send to your guests! In addition to the activities in the party eBook, each Rock Detectives Kit comes with its own CD with an eBook full of activities, puzzles, and experiments that you can use at your party.

ROCK DETECTIVES PARTY PLAN

Activity #1:  Arrival Puzzles & Coloring Pages

Each party pack of Rock Detectives kits comes with a free parent copy of the Rock Detectives eBooks so that you can print and prepare the party activities from the kits before the kids arrive. Each kit has word puzzles, mazes, and coloring pages that you can give to your party guests to occupy them as other guests arrive.

Activity #2:  Create-Your-Own Rock Storage Box

A good geologist always has a way to carry their samples. Create fun storage boxes out of inexpensive items from around your house. Instructions are provided on the Rock Detectives Party eBook. You can use plastic boxes or egg cartons to make great boxes with individual slots for different samples.

Activity #3:  Sample Identity Detection

Print the sample identification and activity pages from the Rock Detectives eBook and let your party guests follow the clues to identify the name of each sample in their Rock Detectives kit. Each kit comes with a hand magnifier to help see the details! We recommend that you use one Rock Detectives kit for every two to three kids at the party so they each have samples to identify and test.

Activity #4:  Panning for Rocks, Minerals & Fossils

Mini Me Geology’s new Earth’s Treasures Geology Sifting Cups are a fun party activity and a great take-home gift. Each 8-ounce jar is filled with natural beach sand, rocks, minerals, and fossils. No two jars are exactly the same so each child has a unique set of samples. To find your hidden treasures, simply pour the contents through a beach sifter as real geologists do. The sand will fall through leaving your goodies behind.

If you don’t have a beach sifter on hand have the kids create their own by layering several layers of aluminum foil and then rolling the ends together to make a bowl. Using the sharp tip of a pencil, poke small holes in the foil to create a homemade sifter that will allow the sand to fall through and keep the treasures on the foil.

If you prefer to make your own sifting gifts, use a small bucket or mason jar and fill it with a mixture of sand, rocks, minerals, and fossils.  Instructions are provided on the Rock Detectives Party eBook. We have bulk rocks and minerals and fossil shark teeth for your panning buckets.

Activity #5:  Geode Cracking

All good geologists break open rocks to see the inside. Kids love to crack open large geodes to see the crystals inside. Instructions and safety precautions are provided in the Rock Detectives Party eBook. Our large geodes make great take-home gifts for your party guests.

Activity #6:  Geology Experiments

All good geologists love experimenting with their samples. Each Rock Detectives kit includes instructions for experiments that you can do during the party like growing sugar and salt crystals, creating metamorphic rock cookies, and much more. Don’t worry if you run out of time, you can print the instructions and let the guests take them home.

Activity #7: Wrap Up with Rock Bingo!

Play Mini Me Geology’s Rock Bingo to wrap up your party. The bingo game is included in the Rock Detectives Party Invitations and Activity eBook. A great gift for winners is rock candy from your local candy store. If you can’t find the candy locally, give us a shout and we can point you to some online sources for bulk rock candy.

Get started planning your party today! If you have questions about our kits or how to throw a successful party, contact us.

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Filed under: Birthday Party Ideas on February 24th, 2019 | No Comments »

Today is German Geologist Friedrich Mohs’ Birthday!

Geologist Friedrich Mohs was born on January 29, 1773, in Gernrode, Germany. Born Carl Friedrich Christian Mohs, he was a geologist and mineralogist who during his career worked at a mine, as a mineralogist for a private collector, and as a geologist for a museum. During his career at the museum, Friedrich began to identify minerals using their physical properties. One of these physical properties was the hardness of a mineral, which led him to create the Mohs Scale of Mineral Hardness in 1812. Friedrich Mohs died on September 29, 1839, at the age of 66.

Still today, we use mineral hardness as a clue to the identity of a sample. The Mohs Scale of Mineral Hardness is a relative hardness scale with 10 mineral samples and several common items such as glass, fingernail, and a pre-1981 penny. Each item on the scale has a specific hardness. Talc, number one on the scale is the softest and diamond, number 10, is the hardest. The Mohs mineral scale and common object are:

In this video we discuss how to use the Mohs Scale of Mineral Hardness with your own samples.

Filed under: Geology Education, Minerals & Crystals on January 29th, 2019 | No Comments »

Thank you for visiting Mini Me Geology! If you are here, you probably love geology or have kids or students who do. As a thank you for visiting us, we have a free 53-page Rock & Mineral Fun Book for you.

Sign up for our newsletter through the blog (top right corner) or on our website. You will get an email with a link to download the book. The Rock and Mineral & Book includes:

• Word Search, Hidden Word, and Crossword Puzzles,
• Coloring Pages,
• Experiments,
• Rock and Mineral Identification Flow Charts,
• Image Galleries,
• Birthstone Details,
• Viktor’s Ice, the prequel novella to the Crystal Cave Adventure series of novels.

We hope you enjoy our Rock & Mineral Fun Book. If you have questions about any of the information in the book or other Mini Me Geology products, please contact us.

Explore Mini Me Geology for Fun, Educations Gifts for Kids

While you are on the website, check out our awesome rock and mineral kits for kids, home school, and classrooms. Each of our kits was designed by a professional geologist who is also a mom, so you can be assured that they are both fun and educational.

At Mini Me Geology, we have a variety of individual mineral samples and geodes, igneous rock samples, metamorphic rock samples, sedimentary rock samples, rock and mineral kits for kids aged 6 and up, identification tools, educational books and teaching resources, coloring and activity books, and geology-themed adventure novels and companion activity books in the Crystal Cave Adventure Series. Plus, Geology Birthday Party supplies and ideas!

Join The Rock Detectives Club for more Geology Fun

For extra fun, join The Rock Detectives Club where every month we post videos about a different rock or mineral, a video where we answer your questions about geology, word puzzles and writing activities, experiments, games, coloring pages, and more! You also get instant access to our new rock and mineral identification flow charts and the Blue John’s Cavern novel and companion activity book. Learn more about The Rock Detectives Club and watch a behind-the-scenes video today.

Filed under: Geology / Earth Science, Kids "Science" Fiction & Activity Books on January 28th, 2019 | Comments Off on Get a Free Rock & Mineral Fun Book for Your Kids!

The release of the Crystal Cave Adventure series is an exciting step that blends fun adventure stories with science. In today’s world when Science, Technology, Engineering, and Math (STEM) curriculum is all the rage, a novel series that can transport kids to a story that is fictional yet has a touch of real science woven throughout the series is a welcome change to many children.

The series, which just released its third book, tells the adventures of young teenagers Emma and Brody as they travel through time to collect rare mineral samples from around the world. In Book 1, Blue John’s Cavern, Emma meets Brody, her new neighbor in Diamond Falls, West Virginia. When Brody discovers that Emma loves rocks and minerals, he offers to take her to meet the famous geologist who lives across the street, Heath Matthews. Mr. M, as the kids call him, is preparing his prized rock and mineral collection for a display at the State’s Natural History Museum. When a thief breaks into the Matthews’ home and destroys the collection, Emma and Brody offer to help recollect the samples. Mr. M gladly accepts the help and then sends Emma and Brody on the wildest ride of their lives when they learn the secret of his collection. The magical, time-traveling Crystal Cave.

Currently, the series consists of:

Book 1, Blue John’s Cavern. After accepting their offer to help, Mr. M promptly sends Emma and Brody is Castleton, Derbyshire England in 1785 to collect a sample of the rare Blue John Fluorite. You can read the full book blurb here to learn more about this amazing adventure and the mysterious young girl who helps them along the way.

Book 2, Rusher’s Gold. Emma and Brody travel to the California Gold Run in 1851 to collect a sample of pure gold but when their plan goes awry they learn that their actions in the past can have dire consequences to their future. You can read the full book blurb here.

Book 3, Black’s Opal. Emma and Brody travel to Lightning Ridge, Australia in 1925 to collect a sample of one of the rarest minerals, the Black Opal. Along the way, they meet a young girl with a secret that just may change their lives forever. As they search for the Black Opal, the kids must avoid stampeding kangaroo, flying boomerangs and survive a goat cart race at the Easter fair. When their escape plan lands them 2000 years into the future, will they be able to get back home? You can read the full book blurb here.

The Crystal Cave Adventure series has a self-contained story in each book with a story arc that carries through all of the books. As they solve one mystery, another mystery begins.

The Crystal Cave Adventure series is available in eBook and paperback at all major retailers. For a free introduction into the series, you can download a copy of Viktor’s Ice, the prequel novella which tells the story of the birth of the Crystal Cave. When Mr. M and his students discover the magical cave and fall hundreds of years into the past, can they survive being stranded in the Arctic Ocean with a longship full of Vikings? What mineral will they find that just might save the day? You can get a free copy at Mini Me Geology, the Author’s Website, or from Prolific Works (formerly Instafreebie).

The Crystal Cave Adventure series is written by a geologist, Tracy Barnhart, who loves all things geology, adventure and time travel! The series is published by Giverny Press.

Filed under: Geology Education, Kids "Science" Fiction & Activity Books on October 4th, 2018 | Comments Off on Crystal Cave Adventures Blends English Language Arts and STEM into an Exciting Novel Series for Kids

Help Kids Learn how Metamorphic Rocks form from Sedimentary Rocks with this fun, edible experiment.

As sediments build up in layers over time, they may become compressed and turn into sedimentary rocks. A significant increase in pressure with low to moderate temperature increases may cause metamorphism to take place and turn the rock from sedimentary to metamorphic. This metamorphic rocks experiment lets kids create their own sedimentary rocks, expose them to high heat and pressure, and observe the changes. These fun “Bread Rocks” are made of edible materials from the grocery store so they are easy and fun to make.

To Make the Bread Rocks, You Will Need:

• Bread (at least three slices – try to use different colors like white, wheat, and/or rye)
• Mini Marshmallows
• Mini Chocolate chips
• White Chocolate chips
• Butterscotch chips
• Wax paper
• Foil

How to Perform the Bread Rocks Experiment

Step 1: Layer three or more bread slices with mini marshmallows, chocolate chips, white chocolate chips, and butterscotch chips in between each layer. You can create the sediment layers in any manner you choose. If you choose to make patterns on one or more of the layers it will help you to see changes in your “rock.” Sketch your rock on a sheet of paper so you remember the pattern and it is easy to compare and see the changes.

Step 2: Place the bread rock onto the waxed paper or foil and sit in a warm location such as outdoors on a hot day or on a stovetop. If you have access to a microwave, heat it for a few seconds on low power.

Observe:  Did the heat cause any changes in the bread rock? Did the marshmallows or chocolate chips begin to melt and change from their original state?

Step 3: Place a piece of waxed paper or foil on top of the bread rock and stand on the rock for one to three minutes to represent millions of years of pressure on the rock. Stand on the bread rock for one minute for each one million years of pressure.

Observe:  Did the pressure cause any changes in the bread rock? Did the marshmallows or chocolate chips change shape or pattern? Are the rocks layers easy or difficult to separate after the metamorphism?

This experiment is great for kids of any age. Beware! The kids may want to eat their metamorphic rocks (eew, gross!) so make sure you wrap the rocks well before the kids stand on them. This is one of the great experiments in our Rock Detectives Camp Guide. If you have any questions about this experiment, contact us and we will be happy to help.

Filed under: Geology / Earth Science, Geology Experiments & Activities on April 25th, 2018 | Comments Off on “Bread Rocks” Make a Fun Metamorphic Rock Science Experiment

Many different mineral crystal geometric shapes exist in the world. In fact, there are too many to list in a simple article without turning this into a book. Determining the geometry of a mineral sample, if there is one, can help you uncover its identity, making it one of the unique crystal properties that geologists use in the evaluation process of a new sample. Crystal geometry is where math and nature collide.

Mineral Crystal Shapes

Many of the shapes that minerals form are common patterns that you learned in in high school geometry class like cubes, rhombohedrons, octahedrons, and hexagons. Halite, pyrite, and galena are classic cube forms. Diamond and fluorite are two well-known minerals that form as octahedrons while calcite is one of the best-known rhombohedra. The rhombohedral calcite shape gives the clear variety, known as Iceland Spar Calcite, its optical properties.

Quartz and its other varieties like amethyst and citrine form a unique shape that has a six-sided pyramid on each end of a six-sided prism. Finding a perfectly shaped quartz with the prism and both pyramids are somewhat rare. The famed Herkimer Diamonds are examples of these perfectly formed crystals. Their name comes from Herkimer County, New York where many beautiful samples were first discovered. Other locales of perfect quartz crystals exist, but only the ones in Herkimer County are the true “Herkimer Diamond.” Although, you will find that most people refer to any perfect quartz crystal by that name.

The most interesting part about the geometry of minerals is that crystals can sometimes form more than one shape depending on how they grows or the environment. Calcite, for example, as mentioned previously, can form nice rhombohedrons but it can also form shapes like scalenohedrons, hexagonal prisms, and pinacoids. Fluorite also forms in multiple shapes including octahedrons and cubes.

Mineral crystals also grow in unique forms when two or more crystals grow together.

Sometimes you will see a mineral that looks like two crystals that have grown together at slightly different angles. This is called a “twinned” crystal. Staurolite is a commonly twinned mineral. A “staurolite cross” is two staurolite crystals that grow perpendicular to one another. At times, the crystals may be slightly less than perpendicular, as shown in the photograph above.

A mineral “cluster” or “druze” forms when many crystals grow in a group or layer and are attached to one another side by side. Geodes often have druze of quartz, amethyst, and citrine inside. The amethyst shown in the photo is a druze with numerous side-by-side crystals.

Crystal Shape vs. Mineral Cleavage vs. Fracture

People sometimes confuse mineral shapewith mineral cleavage but the two are actually different. The shape is a natural form that the mineral will take as the crystal grows. Cleavage is the tendency of a crystal to break along planes within the crystal. Minerals with cleavage break into particular shapes such as cubes, rhombs, octahedrons, and thin layers.

Some minerals have “perfect cleavage,” which means the mineral breaks smoothly along the cleavage plane without any rough edges. The diagram below shows some of the common cleavage types and associated minerals.

Minerals that do not have cleavage (do not break into specific shapes) will fracture when broken. Even minerals that naturally grow in perfect shapes, such as cubes or prisms, may fracture when they are broken and will no longer be a cube or prism. Two minerals that can have beautiful crystal forms but fracture when they break are quartz and pyrite.

A common fracture pattern is a conchoidal fracture. Minerals and rocks with a conchoidal fracture will have a distinctive swirl pattern on the surface after it breaks. In addition to quartz and pyrite, the igneous rock obsidian exhibits conchoidal fracture patterns when broken.

Learn more about Mineral Crystal Geometry

At Mini Me Geology, we love the geometry of minerals so much that we created a fun activity kit for kids that focuses on these fun properties. We designed the Rock Detectives Crystal Geometry kit for kids ages 6 to 12, but older kids and adults secretly love it, too. The Crystal Geometry Rock Detectives kit comes complete with:

• 6 Large Mineral Samples: muscovite, fluorite, calcite, citrine, pyrite and agate geode
• Mini Me Geology custom Hand Lens with 3X and 6X magnifications
• 30-page, full-color eBook on CD that includes mineral information, sample identification activities, puzzles, coloring pages, experiments, an adventure story writing exercise for your geology detective, and activities including making a personal geologist’s field notebook and your very own rock collection box.

If you have any questions about mineral crystal shapes or any of our kits, please contact us and we will be happy to answer your questions.

Filed under: Geology / Earth Science, Minerals & Crystals on February 27th, 2018 | No Comments »

The 12 Rocks of Christmas – (Sung to The 12 Days of Christmas)

On the first day of Christmas, my true love gave to me
A Mini Me mineral kit

On the second day of Christmas, my true love gave to me
Two syenite,
And a Mini Me mineral kit.

 On the third day of Christmas, my true love gave to me
Three limestone,
Two syenite,
And a Mini Me mineral kit.

On the fourth day of Christmas, my true love gave to me
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the fifth day of Christmas, my true love gave to me
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the sixth day of Christmas, my true love gave to me
Six garnet schists,
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the seventh day of Christmas, my true love gave to me
Seven monzonite,
Six garnet schists,
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the eighth day of Christmas, my true love gave to me
Eight slabs of slate,
Seven monzonite,
Six garnet schists,
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the ninth day of Christmas, my true love gave to me
Nine granite samples,
Eight slabs of slate,
Seven monzonite,
Six garnet schists,
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the tenth day of Christmas, my true love gave to me
Ten siltstone,
Nine granite samples,
Eight slabs of slate,
Seven monzonite,
Six garnet schists,
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the eleventh day of Christmas, my true love gave to me
Eleven coquina,
Ten siltstone,
Nine granite samples,
Eight slabs of slate,
Seven monzonite,
Six garnet schists,
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit.

 

On the twelfth day of Christmas, my true love gave to me
Twelve volcanic breccia,
Eleven coquina,
Ten siltstone,
Nine granite samples,
Eight slabs of slate,
Seven monzonite,
Six garnet schists,
Five lumps of coal,
Four obsidian,
Three limestone,
Two syenite,
and a Mini Me mineral kit!

Filed under: Geology / Earth Science, Minerals & Crystals, Rocks - Igneous, Sedimentary & Metamorphic on November 29th, 2017 | 1 Comment »

At rock camp, we perform the salt crystal growing experiment. I use a portable coffee maker to heat the water. We use equal parts salt and water and grow several small salt crystals on the string that dangles into a mason jar. Success! However, if you really want to grow BIG crystals, use a stove top to make your solution. You can do this to begin with or after you have a few small crystals on the string. Here’s how.

The Stove Top Method

Growing salt and sugar crystals from a solution is a great experiment to teach kids how igneous rocks form from molten rock. The size of the crystals that you grow on your string is limited by the amount of salt and sugar that you can dissolve into your solution. Using the stove top to heat your water often allows you to dissolve a little more salt or sugar to grow a little more and  a little bigger crystals.

To create a solution on the stove, pour enough water to fill the mason jar into a small pot. As the water heats, pour salt or sugar into the saucepan and stir until it is fully dissolved. Keep adding more salt or sugar until the solution is saturated and no more will dissolve. Pour the solution into the mason jar and replace your string and secure it to the top of the jar.

If you are using this method from the beginning of the experiment, fray the string slightly before placing it into the soltuion to give the crystals something to grow on. If you are replacing the solution, the crystals will grow on top of the seed crystals already on the string.

How Big Can Your Salt or Sugar Crystals Get?

That depends on your patience. You can replace the solution as many times as you want to grow bigger and bigger crystals. For a fun twist, add a touch of food coloring to your solution to created colored crystals.

Let us know how how this method works for you. We’d love to see pictures of your crystals.

Filed under: Geology Education, Geology Experiments & Activities on October 10th, 2017 | No Comments »