This Month's Featured Rock:
OBSIDIAN
Obsidian is a black, glass-like igneous rock. It is called an "extrusive" igneous rock because it is formed when lava is thrown from a volcano. When the lava is thrown from the volcano, it cools so quickly that it does not have time to form crystals, which makes it look like glass. Obsidian is formed of mostly feldspar and quartz, which is the same major minerals found in granite, rhyolite and pumice but because of the quick cooling, it looks completely different. Obsidian has very sharp, curved surfaces when it is broken. This curved surface where the rock breaks is called a conchiodal (kŏng-koid'l ) fracture and looks similar to a shell. One variety of obsidian called "snowflake obsidian" has which snowflake-like spots on the rock. The white areas are actually spots where the rock has begun to deteriorate. Obsidian is a popular, yet not very common rock. One of the best locations of obsidian rock in the United State is Obsidian Cliff in Yellowstone National Park. Check out these links to get your own obsidian or snowflake obsidian samples! |
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February's Featured Item:
CRYSTAL GROWING
Punxsutawney Phil predicted six more weeks of winter so load up on great indoor, educational fun with our crystal growing kits! Choose from amethyst purple, rose pink, diamond white, sapphire blue, jade green and topaz yellow. All purchases come with a set of free dinosaur tattoos for a limited time only. Get your crystal growing kits today! | |
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Hello Kids & Parents! ,
Welcome to The Rockland Gazette! Each month we provide you with feautures about rocks and minerals and geology fun. We hope you enjoy this month's newsletter!
Sincerely,
The Mini Me Geology Team! |
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It's Your Fault!
We've all heard that phrase before but it is a little different when we are talking about rocks. Faults are breaks in the rocks that make up the Earth's crust that cause earthquakes when they move. However, joints are breaks in the rocks where no movement occurs.
 There are basically three types of faults: normal, reverse and tear. Normal faults occur where the rocks pull apart and the rocks on the upper side of the fault slide downward. Reverse faults occur where the rocks are pushed together and the rocks on the upper side of the fault slide upwards. Tear faults move sideways instead of up and down, just as if the rocks were being torn apart.
Hey Kids! Take a look at this photo and find the two gray layers with the white layer in between. Follow the layers from left to right. Do you see the fault line? Was the fault and normal, reverse or tear fault? (Hint: The rocks on the left are on the upper side of the fault)
Answer: Normal Fault - The rocks on the upper side of the fault are lower than on the bottom side of the fault indicating downward (pulling apart) movement. |
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February Birthstone - Amethyst
Amethyst is actually a purple form of the  mineral quartz. Amethyst has a white streak and appears glassy. Like quartz, amethyst is a 7 on Mohs Hardness Scale.
The most common use of amethyst is for jewelry and is considered a semi- precious stone. Many collectors of amethyst find beautiful specimens in geodes. Click here to get your own sample of rough amethyst! |
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February's Featured Ask-a-Geologist Questions 
Q: What is in magma that makes up a rock?
A: Magma is the term used for liquid rock which forms deep below the Earth's surface. Magma can be composed of many different things such as silicates, alkalis, iron and magnesium. The composition of the magma will determine the type of rocks which it will eventually form.
Q: What rocks are changed by high pressure and high temperature?
A: The change of a rock by high temperature and pressure is called metamorphism. This is the process by which metamorphic rocks are formed. Any rock can be changed by metamorphic processes.
Q: In what parts of the world can sandstone rock be found and what are some of its uses?
A: Sandstones can be found at worldwide locations. They are often used as building materials and in industrial processing applications (e.g. grind stones). A natural use of sandstone is as a reservoir for water, oil and gas. The spaces between sand grains can be either open or filled. If the spaces are open, sandstones make good places for water, gas and oil to be stored below the land surface.
Q: What term for metamorphic rock with banded texture?
A: You may be referring to "foliation" which is the layering within a metamorphic rock. Foliation occurs when there is a strong pressure applied to the rock in one direction, just like when you put your hands flat together and push. When this pressure is applied, certain minerals, like mica and chlorite, grow with their long direction perpendicular to the pressure. This make the rock appear with layering and/or banding.
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February's Word Find Puzzle  Did you know that Mini Me Geology offers free word puzzles and cross-word puzzles? Just click here and print your favorite puzzles! We will post a new puzzle each month. This month's puzzle is all about minerals. Grab a crayon and see if you can find all of the words! | |
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