Crystals Can Form Great Shapes

There are many, many different crystal shapes in the world.  In fact, there are too many to list in a simple blog post!  Determining the shapes of different minerals can help you uncover their identity. Some of the most common minerals and their shapes are shown in this fun image.  The most interesting part about crystal shapes is that minerals can sometimes form more than one shape depending on how it grows or its environment! Do you have any fun minerals with great shape?

Sometimes you will see a mineral that looks like two crystals that have grown together.  This is called a “twinned” crystal. Staurolite is a commonly twinned mineral.

Minerals can also form where many crystals form in a group or layer and are attached to one another side by side.  This is called a mineral “cluster” or “druze.” Quartz, amethyst and citrine are commonly found in a druze form inside geodes.

What kind of minerals do you have and what shape are they? We’d love to hear from you in the comments and post a picture here or on our Facebook page!


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Ask-a-Geologist #13: Do I need a geology degree to be a jewelry designer?

Hi everyone, my name is Tracy Barnhart and I am the professional geologist here at Mini Me Geology and I am back with another awesome question for you about geology careers.

Christina wrote to us and asked: “I am a 26 year old aspiring jewelry designer. I have always been fascinated by rocks and stones. I like to use natural materials in my jewelry, rather than glass or plastic. Would geology be a good place to start? It sounds like there would be a few years of school before I could make this dream happen. I didn’t see this type of career listed, and would like to know if I’m on the right track. My dream would be to eventually open a store where I make all the merchandise.”

What Christina is referring to when she says that she did not see the career listed is an article we have on the dig into geology website about different careers in geology. Well Christina, I think this is a great question because the career you want as a jewelry designer is not the same as a geologist but since you want to use natural rocks and minerals in your designs it would really help you to know some of the things that geologists learn in school.

If I were you, I would not get a college degree in geology. While some of the classes would be useful for you, a lot of the classes you would be required to take for your degree would have nothing useful for you as a jewelry designer. If you pursue a geology degree is will be expensive and not all of it would be useful.

Now if you are working on a college degree and your school requires science credits for graduation or if you just want to ask to audit a few classes, I would suggest that you take the first introduction to geology class where they teach you about rocks and minerals and usually have the classic “rock test” and a mineralogy class where you will learn more detail about the formation of minerals which are most commonly the stones that jewelry designers use.

If attending a class is not a possibility for you, I recently posted a list of my absolute favorite rock and mineral books on our blog that I have in my own library. These books can give you some great introductory information about different rocks and minerals and you can always email me and I’d be happy to help you learn about rocks and minerals.  I hope this helps you a little bit Christina and I sure would love to see your jewelry when you get your business up and running.

Remember to keep your questions coming in through the dig into geology section on our website or email us at Please comment below and subscribe to our channel so that you get the next installment of ask a geologist. Until next time, rock on everyone!

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Help! I Have to Teach Rock and Mineral Identification and I’m Not a Geologist!

Have you ever had this thought? “Help! I have to teach rock and mineral identification and I’m not a geologist.” Identifying rocks and minerals is difficult. Even the most experienced geologists are stumped sometimes (often when an elementary student hands you a random rock they found on the playground and want to know what it is on the spot!). Minerals can have many colors and shapes while rocks sometimes just look alike.

I often see people on the internet explaining all of the rock and mineral activities that kids can do when many of them really will not teach a child much about rocks at all. I think that if you are going to teach kids about rocks then you should not give them cartoon rocks with feet or have them solely painting pebbles. I have my own aversions to tumbled rocks as it is, but that’s another blog post.  Rock and minerals are fascinating and something that kids can love their entire lives, even if the pictures do not have feet.

To help teachers and homeschool parents really teach kids about rocks and minerals, I’m writing a book titled “Help! I Have to Teach Rock and Mineral Identification and I’m Not a Geologist!” You can use this book with samples that you have at home or you can get a small kit along with your book. In the book, I’m detailing the tests and examinations that geologists do to determine the name of a rock or mineral. The book is broken into sections for minerals, igneous rocks, sedimentary rocks, metamorphic rocks and the rock cycle and has all of the information that you need to explain the identification process to your students and suggested exercises to reinforce the concepts. This book will not discuss the geologic time scale so if you have concerns over that topic, this new book will help you introduce geology in a fun and informative way that will make your kids enthusiastic about the world around them without any “bigger picture” questions.

The book is set to launch on March 25, 2014! We are accepting a few beta readers. If you are a teacher or homeschool parent and would like an advanced copy of the book, email me at All I ask in return is your honest feedback about the book. I want this to be fantastic and useful and fun!


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Ask-a-Geologist Q&A Video #12: How do you clean streak plates?

Our readers have some amazing questions and this week is no exception. In fact, this is a very popular question about cleaning your streak plates.

Several of our readers have written to us and asked:  How do you clean streak plates?

In case you are not familiar with streak plates, they are little pieces of unglazed porcelain tile that you use to test the streak color of a mineral. There are black streak plates and white streak plates. You use the black plates for light-colored minerals and white plates for dark-colored minerals. To test the streak, you rub the mineral across the streak plate and see what color shows up on the plate. That is the streak or the color of the mineral in powdered form. When you do the test you need to rub hard on the streak plate because you are trying to crush part of the sample into a fine powder. Over time the plates will become dirty and you will want to clean them.

There are a couple of things that you can do to clean the streak plates. For some of them, you can soak them in warm soapy water for a few minutes then use a kitchen sponge to scrub the surface. This works pretty well to remove the powder of some of the softer minerals. Now a streak plate is about a seven on the Mohs Hardness scale so any mineral that is a seven or higher on the scale will not show a streak because they are harder than the plate. However, these harder minerals will scratch the surface of the plate making them harder to clean because mineral powder gets ground into the porcelain.

For plates that are older and scratched you can use this handy scrubber called the Magic Eraser. These are made by Mr. Clean and you just get them wet and then rub them over the streak plate and they come clean. Over time the plates will get scratched and stained to the point where even the magic eraser won’t work and you will need to replace them but routinely cleaning you streak plates will help keep them nice for many uses.

Remember to keep your questions coming in through the dig into geology section on our website or email us at  Please comment below and subscribe to our channel so that you get the next installment of ask a geologist.  Until next time, rock on everybody.

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Rock & Mineral Books that I Love

I get a lot of questions here at Mini Me Geology about rock and mineral books. While I write all of our books about the identification of rocks and minerals, one book that I will not attempt is a compilation of every rock and mineral type known. Why? Because there are so many fabulous books already out there. I have several sitting on my bookshelf that I truly love so here is my list just in case you want to add to your own rock and mineral book library.

  1. Smithsonian Rock and Gem – This is a big book and a little on the expensive side but if you want fabulous images this is the one for you!
  2. The Encyclopedia of Gemstones and Minerals – The version I have of this book is fairly old, but has tons and tons of fun information.
  3. Simon & Schuster’s Guide to Rocks & Minerals – This is a classic for anyone who is thinking of a career in geology. I love this book for reference information. If you just want a fun book with great images I’d go with the Smithsonian book but for true, diehard rockhounds, Simon & Schuster’s is for you.
  4. A Golden Nature Guide: Rocks and Minerals – The version I have of this book is really old, older than I am actually, but I love this little book. My copy is stamped $2.95!
  5. A Golden Nature Guide: Fossils – If you are in to fossils, this Golden Guide is a great starter book. My version is from the early 1960’s and at $1.95 was a total bargain. I wonder why the fossil guide was cheaper than the rock and mineral guide?
  6. 1000 Facts on Rocks and Minerals – This book is great for younger kids and students who like rocks but are not too interested in super technical details.

So that is my bookshelf. Okay, so I have a bunch of books and notebooks from college and graduate school too, but I doubt you’d be interested in those or if you are a geologist too, I bet you’ve read them!

If you have any questions about these books or need a recommendation for yourself, a child or a friend, please email me and I’ll help you out!

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Ask-a-Geologist Video #11: Why do pumice and scoria have holes and granite does not?

Hi everyone, today we have another great ask-a-geologist question from one of our fabulous readers. Peter wrote to us and asked:  Granite, pumice, and scoria are igneous rocks, but why doesn’t granite have airholes, but the other two do?

Hi Peter, these three rocks that you asked about are all igneous rocks that form from volcanic magma. The reason that pumice and scoria have holes in the rock and granite does not is due to the way they form. This rock is a piece of granite, which is an intrusive igneous rock. It formed inside the volcano when magma was allowed to cool underground. Sometimes, magma will inject into cracks in the rock surrounding the magma chamber and over time will cool very slowly because it isn’t exposed to air. One way to tell if a rock cooled slowly is the grain size of the rock. Granite has mineral grains that are very easy to see. The are medium to large grains and you can tell the difference in the dark micas, clearer quartz and the pink or white feldspar.

Pumice and scoria are extrusive rocks and form outside of the volcano usually on top of lava flows. The top of these lava flows become very frothy and when they cool the gasses in the lava expand and escape forming air hole or vesicles in rock. These rocks are slightly different. Pumice is usually a light colored rock and forms on slow moving, viscous lava flows, and is light and floats on water. Scoria sample is a dark red color and forms on a more liquid lava flow, has larger holes than pumice, is slightly heavier and does not float on water.

Remember to keep your questions coming in through the dig into geology section on our website or email us at Please comment below and subscribe to our channel so that you get the next installment of ask a geologist. Until next time, rock on everybody.


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Streak Can Tell You A Lot About a Mineral

Geologists use many tests to determine the identity of a mineral. Streak can be one of the most important tests when trying to tell two similar minerals apart. A mineral’s streak is its color when the mineral in is powdered form. How do you get a powdered form? Simple. Geologists uses streak plates to powder the mineral to test the streak.

A streak plate is a piece of unglazed porcelain tile. When you rub the mineral sample on the plate, the powder will stay on the tile. Some minerals have a streak color that is the same as their outward color, while others have a streak color that is totally different. For example, azurite has a blue outward color and a blue streak and limonite is a yellow-brown color both outside and in powder form. Conversely, yellow sulfur has a white streak while gray hematite has a cherry red streak color.

For details on how to perform the streak test with your own samples and testing plates, you can read this article in the Dig Into Geology of our website.


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Ask-a-Geologist #10: What Are The Remains Of Once Living Organisms Found In Sedimentary Rocks?

Hi Everyone! This week Shane wrote to us and asked: What are the remains of once living organisms found in sedimentary rocks?

Hi Shane, Fossils are the remains or impressions of once living organisms that you can find in sedimentary rocks. There are two basic types of fossils that geologists and paleontologists talk about. These are body fossils and trace fossils. Body fossils are a real body part of an animal such as a dinosaur bone or a shark tooth. A trace fossil is something that shows evidence that something was there such as tracks, burrows, trails, molds, casts, and impressions.

The shark teeth and snail shell that I show in this video are examples of body fossils. These types of fossils can either be the original shell, tooth or bone material or the fossil could be altered somewhat but the shape and details of the original are intact. The rocks that I show here are fossiliferous limestone. This rock gets its name from the abundant fossils that are a part of the sample. Some are bits of shells but some are trace fossil such the impression of a shell and areas which appear to be burrows from animals. You can also see a fossil that looks like a snail shell that was replaced by limestone but holds onto the shape of the original part. Other trace fossils that you might see in books or collection include leaf and fish impressions that are common in sedimentary rocks.

Remember to keep your questions coming in through the dig into geology section on our website or email us at Please comment below and subscribe to our channel so that you get the next installment of ask a geologist. Until next time, rock on everybody.



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The Geology of Sochi, Russia – Home of the 2014 Winter Olympics

Hi Everyone, today I’m writing about a question that I’m sure most of you die-hard Winter Olympic fans are asking yourself. What is the geology of Sochi, Russia?! With those beautiful buildings, the amazing Black Sea and those oh so fabulous mountains in the backdrop, the resort town of Sochi looks like a nice place to visit.

The geology of Sochi, Russia is much more complicated than you might think. Sochi is situated along the shores of the Black Sea. A short, 25 miles away loom the Caucasus Mountains, where they are hosting all of the skiing, snowboarding and sliding events at the 2014 Olympics. These majestic mountains are relatively young in geologic years and form from the collision of continental plates in the area.

North of Sochi is a major thrust fault, called the Main Caucasus Thrust fault. In this area, rocks from the northern part of Russia and moving over and ending up on top of rocks from the south. There is another fault called the Racha–Lechkhumy Fault Zone that is located south of the Main Caucasus Thrust. This fault helps to build the mountain range higher and bigger.  The area where they are skiing, snowboarding and sliding at the Sochi Winter Olympics is located between these two faults.

The town of Sochi itself sits in a basin between the mountains and the Black Sea. This basin is filled sediments that were deposited by a main river, the Mzymta River, that flows into the Black Sea and debris from the mountains.  The landscape of Sochi includes wetlands and sandy beaches making it an ideal resort town and somewhere that looks very nice to visit.  This unique geology presented some interesting construction problems for the crews working on Olympic venues.  If you are interested in the construction aspect of the Olympic venues, you can read more here.

Photo:  Caucasus Mountains
U.S. Geological Survey Department of the Interior
USGS U.S. Geological Survey
Photograph courtesy of V.M. Kotlyakov, Russian Academy of Sciences, Moscow


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Help! How do I use my new My Rockin’ Collection Rock or Mineral Kit?

I’m so glad you are excited about your new My Rockin’ Collection rock and mineral kit. Your kit has everything you need to identify and learn about your samples. To add to the fun, I created four short articles about using the tools in your My Rockin’ Collection junior or deluxe rock and mineral kits to add to your geology experience.

There is one article each for the mineral kit, igneous rock kit, sedimentary rock kit and metamorphic rock kit at the Dig Into Geology section of our website. Plus, each article has a free identification flow chart that you can download and print that will give you another way to identify those samples.

As always, if you still need help or have questions about your new rocks and minerals, email me, Tracy Barnhart, at and I’ll be happy to help you! Rock on, everyone!

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