Doing Some Moving

For anyone who has been wondering why I have made only one post during the last two months I now give my answer. I have been learning more and more about the Internet and have realized that I can do more with the settings, appearance, ect. of my site if I create my own website through another blog. I am sorry if any of you find this inconvenient and I hope that you will continue to enjoy my posts about rocks and minerals on the new site!
Sincerely,
Jake.
P.S. the new website in infantile right now, but you can visit it to see what I've been up to through the following address: http://explorerocksandminerals.com.

Heulandite: The Coffin Mineral

First off please allow me to appologize for the delay. I have been working on other projects a lot lately and haven't found the time to keep this blog up-dated. Also please forgive the brevity of this post. Again this is due to my lack of time.

The zeolite mineral heulandite was named for John Henry Heuland, an English mineral dealer. It is one of the most common zeolites--a family of silicate minerals. Heulandite is often coral-pink, but it can also be brown, white or red. It has either a pearly or vitreous luster and a Mohs hardness of 3.5 to 4.

Heulandite’s crystals are an oddity among minerals. If they are not altered by a natural processes then they will be shaped like the coffins from Western movies. These crystals can be distorted during their formation, which causes them to look differently.

Heulandite can be used for the myriad of purposes that many other zeolites serve. It has no use in the jewelry industry, but collectors like me love to collect it!

Heulandite is found in basalt like many of its fellow zeolites. Sources of the mineral include: India, Iceland, the Faroe Islands, Scotland, the Canadian province of Nova Scotia, and the American states of Washington, Idaho, Oregon, and New Jersey.

Lepidolite: the Purple Mica

Lepidolite is part of a group of minerals known as the micas, which I have written about before. I have chosen to cover lepidolite separately because it has a few unique properties, the most noticeable being its attractive color.

Ultimately, what sets lepidolite apart from the other micas is the presence of lithium in its chemical structure. In fact, one of the more common types of mica, muscovite, can be turned into lepidolite under the right conditions if lithium is present.

Lepidolite shares many traits with the other micas, but its individual chemical structure imparts a few properties that the others cannot claim. Like its cousins, lepidolite’s crystals are six-sided, very flat, and so soft that they are usually distorted. The crystals are often grouped as stacks and they’re commonly found as flakes. The thin crystals or flakes are flexible, a characteristic which is rare in the mineral kingdom. Lepidolite has a vitreous to pearly luster and a Mohs hardness of only 2.5 as do the other mica minerals.

Lepidolite’s first visible property that differs from lithium-free mica is its violet color, though it can take pale pink, or rarely gray or yellow. And it can be triboluminescent (when pressed it will emit little flashes of light in the dark.)

Lepidolite was once used as an ore of lithium, but the lithium content varies in lepidolite so people found other sources of the metal. Lepidolite is found chiefly within rock formations called “granite pegmatites” in places like: Madagascar, Sweden, the Brazilian state of Minas Gerias, and the American states of California, Connecticut, and Maine.

Sulfur: Mineral or Element?

Is sulfur a mineral or an element? Actually it's both. Sulfur is a type of mineral known as a native element. I have written an entire post devoted to this group of minerals, which can be accessed through the link above, so that you can learn about them.

Sulfur always displays a lemon-yellow color and for the most part is translucent. Its crystals belong to the orthorhombic crystal group and look like octahedrons made with isosceles triangles. Sulfur does not always take this form, however. It is often found as crusts or masses. It is very soft (only measuring at a 2 on the Mohs Scale) and it has a very low melting point. Sulfur is flammable, burning with a blue flame. (If you have any then you shouldn’t try this, though. Not only will you ruin a fine specimen, but you’ll also release a toxic gas!) Sulfur has a vitreous luster, but its masses are sometimes earthy. It has a white or yellow streak. Sulfur often exhibits a smell like rotten eggs, which can be a helpful trait when trying to identify it.

Sulfur has a long history of use. In ancient times it was used as a pigment and a tonic. Then, around the time of the Renaissance, it was employed to make gunpowder. Today sulfur is a very important substance in industry; I have read that the state of a nation’s industry can be guessed by its level of sulfur consumption. Most of the sulfur used in industry is converted into sulfuric acid, which is used to make pigments, explosives, sheet-metal, car batteries, and detergents. What isn’t made into sulfuric acid can be used in paper making, fungicides, and insecticides.

Sulfur is often found near volcanic steam-vents as crusts and masses. Good crystals can be uncovered in vugs (cavities) within limestone. Some sources of the mineral include: Sicily, Russia, Poland, Japan, Louisiana, Texas, and Wyoming’s Yellowstone National Park.

Limonite: Nautral Rust

Limonite a term which refers to an un-identified mixture of hydrated iron oxides and hydroxides--it is pretty much just naturally-occurring rust. Limonite is amorphous meaning that it has no crystal shape, and therefore it can’t really be considered a mineral, but I have never heard it classified as a rock. Perhaps it falls into the mineraloid category. Limonite is the color of rust and is found as massive, earthy lumps. For the most part is has an earthy or dull luster, which means that it does not reflect light. Limonite’s amorphous structure seems to be the only thing that separates it from goethite another mineral composed of iron oxides and hydroxides. Goethite forms fibrous crystals.
Limonite is famous for staining things with its yellow-brown color. In fact when you pick up a piece it will probably leave a dusty brown residue on your hands. Limonite is a coloring-agent in some soils and rocks, and it often colors agates and cherts. Sometimes this coloration occurs only on the surface forming a rust-colored crust, but it occasionally penetrates deeper. If you ever look for rocks in Lake Michigan or Lake Huron you will likely come across a great many chert pebbles that have been colored by limonite.
Limonite usually forms when other iron-bearing minerals (such as hematite) weather upon exposure. Since limonite is composed of hydrated iron oxide it will revert to hematite when it dries out. It also forms what is known as “bog ore”. Bog ore is limonite that forms as chunks below the water in marshlands and lakes.
Limonite was once used to make a kind of paint called “ochre”. It may serve as a minor ore of iron but I am not sure about that. It can be found theoretically wherever iron is present and seeing as iron is the fourth most plentiful element in the earth’s crust there are a great many potential sources.

Rock-Collection Labeling Made Easy

When I posted my piece on rock collecting for kids I had to leave this part out because if I hadn't the article would have been far too long. Since it is really a piece of my previous post it is still geered toward those who want to introduce the hobby to their kids, but please don't let that bother you. This post can be useful to anyone who is starting a rock collection and would like to find an easy way to label it.

Once your children identify their specimens they can label them. They can make labels by cutting sections of index cards and writing all of the information that they want on them. My labels usually include: the name of the specimen, the name of the specific site where I found it, the name of the county where the site is located, the nearest city to that site, and the state in which that city sits—in that order. For example, your child’s label might look something like this:
Jasper
Rockyland Ridge Mine
Custer County
Custer
South Dakota
What if the site where your kids found their rocks is a farm or even your driveway? You can label the sight after the name of the farm such as, “Maple Creek Dairy Farm,” or “Farmer John’s Sheep Farm,” or in the case of your driveway you can label it as “Smith Family Driveway,” or “Smith Site.”

If some of that information is missing then your kids can just omit it from the label. Some of my labels mention only the name of the mineral and the state where I found it. A few only mention the mineral's name. 


 

Rocks and Minerals for Kids: How to Get Started

Looking for a fun hobby to introduce your kids to? Have you ever considered rock collecting? Rock collecting (or “rockhounding,” as many in the hobby call it) is very popular these days. I started rock collecting when I was about five years old and I’m still doing it today.

The first thing you are going to need to start a rock collection is a few rocks. There are two ways that your kids can start their collections: they can find them themselves or they can buy them from places like museum gift shops.

Finding nice specimens in the field is not as complicated as you might think. If you have a gravel driveway then that can be your first place to look. Look for anything that stands out from the other pebbles in the driveway and save it as a specimen. Another great place to search is a farm field. Every time a field is plowed a lot of rocks are heaved up with the soil and will just sit in the field until someone finds them or they are plowed back under. Just ask a farmer if you and your children can spend a few hours searching through his field. In most cases he’ll be more than happy to let you take some of those pesky rocks away. You can also search for public accessible rock-collecting sites on the Internet.

Now that you’ve found some places to go rock hunting you can start planning your trip. Your children will each need something to carry their rocks home in. A cloth bag works really well for this purpose. If some of the specimens are fragile you can wrap them in toilet paper to protect them from harm. You may also want to take a pad of paper and a pen with you so that you can record the name of the site if you want to remember that later.

Once you have found a few nice specimens and brought them home they may need to be cleaned. If they have any dirt on them your kids can scrub that away with old toothbrushes and soapy water. A note of caution: it is a good idea to test the rocks by wetting the corner of the specimen before cleaning them. Some rocks will actually dissolve in water!

After the specimens are cleaned you can store them. I use plastic beading boxes with twenty compartments each to house my collection. This keeps the rocks and their labels together (I will talk more about the labels shortly) and allows you to store them in a compact space. These boxes cost less than five dollars a piece.

Now it’s time to identify the rocks. For this you will need a good rock and mineral identification book. These books explain how to identify minerals using their color, the streak test, the hardness test, and a lot of other techniques. Such books are a very good investment. You may want to consider purchasing a fossil identification book as well, since your kids may find a lot of fossils.

The Zeolites: A Family of Useful Minerals

The term zeolite denotes a family of minerals with similar chemical structures. They are all aluminum- silicate minerals that have crystal structures which resemble honeycomb. Zeolite minerals are often found in vesicles inside volcanic rocks, especially basalt. There are about fifty minerals in the zeolite group.
The honeycomb-like structure found within the zeolites includes a lot of tiny tunnels and pores that allow water to pass through the mineral without affecting its crystal; and these pores are all of a uniform size. Now ask yourself: does it seem that something like this could occur by chance or do you think it points to the design of a Creator? It’s something worth thinking upon.
Because of the properties that I mentioned above, zeolite minerals are often used to filter very small particles out of air and water. They can also hold water like sponges so they are used thus and in place of potting-soil in some agricultural applications. Zeolites are used to clean up oil spills and radioactive waste as well.
Zeolite minerlas are found in many different countries far too numerous to mention here. I plan to write about some of the members in this family of useful minerals soon and their properties and locations can be discussed on an individual basis.

Antimony's Toxic Legacy

When I made my last post I said that I planned to talk about the metal antimony’s toxic legacy. I researched the topic and found nothing concerning the symptoms of antimony poisoning save that antimony compounds attack certain tissues in the body. I have read that consuming large enough doses of antimony or its compounds is lethal. In fact, antimony’s very name is said to come from a story in which a monk named Valentinus added stibnite to the other monks’ food in an attempt to help them gain weight. Unfortunately the stibnite did not have its desired effect and the monks died. After that it was called anti-monachium which means “against monks.”
So where does this leave our shiny, gray mineral stibnite? Well if you were to eat a large enough quantity of stibnite you would die, but handling the mineral isn’t the same as consuming it. I have always read that you should wash your hands carefully after handling stibnite. Don’t let young children touch it--keep it out of their reach. I keep mine in a plastic “perky box” to minimize contact with it.
Stibnite is a beautiful mineral, one that I am happy to include in my collection. It should not be feared, but rather respected. Follow the safety rules that I have mentioned above and use common sense when collecting stibnite.

Stibnite: Toxic Beauty

The metal antimony was once called stibium, which is why it is represented by an Sb on the Periodic Table of Elements. Stibnite’s name stems from the fact that it is an ore of antimony.
Stibnite is a steel-gray or lead-gray mineral that has a metallic luster (although it can tarnish, turning black) Stibnite’s crystals are orthorhombic and are usually blade or needle-shaped. Its crystals are slightly flexible so they can be bent or twisted. I wouldn’t do this with any good specimen, but it could be a helpful test to help identify the mineral. Stibnite measures only a 2 on the Mohs scale of hardness.
Stibnite is still the main ore of antimony, which has been used since ancient times (though for many years it was confused with lead) Today antimony is mixed with other metals to form alloys that are used as coverings for cables and in car batteries. Stibnite itself is used in the making of matches, percussion caps, and fireworks.
Stibnite is found in places like: Japan, Serbia, Macedonia, Romania, Peru, California, and Nevada.
A final word of caution: stibnite is a poisonous mineral! Antimony is toxic and it imparts this property to its ore. Always wash your hands carefully after handling stibnite. This topic will be discussed further in my next post.

Anhydrite: Warning! Keep Dry!

The word “anhydrous” means “lacking water.” So, when gypsum looses the water molecules that help make up its chemical composition “anhydrite” is an apt name for the new mineral that results.

Anhydrite commonly forms when gypsum dehydrates, but it can form in other ways. It is often found between layers of gypsum and even between gypsum and halite. Because it usually forms when gypsum dries out the layers of anhydrite are often contorted.

Anhydrite crystallizes in the orthorhombic crystal system, but it is usually found in massive or fibrous habits, the latter looking a bit like satin-spar selenite (a variety of gypsum that you can read about in my March 17, 2011post Gypsum: The Mineral About the House) Anhydrite can be distinguished from gypsum by the fact that it is a little harder. Anhydrite is usually white or colorless, but it can also be lavender, reddish, bluish, or gray.

I’ve already stated that gypsum becomes anhydrite when it looses its water, but if the anhydrite absorbs water then it will become gypsum once again. Because of this, anhydrite can be ground into a powder and used to make concrete and plaster of Paris. This property also makes anhydrite difficult to find. Since it so easily reverts to gypsum, anhydrite tends only to be found deep underground where it won’t be exposed to much moisture.

Anhydrite can be found in such places as: Mexico, Cuba, Peru, Chile, Canada, Zaire, and the American states of: Alabama, Michigan, Louisiana, and Texas.

I hope that you’ve enjoyed this piece about anhydrite. I have one final note for collectors which concerns anhydrite’s relationship with gypsum: if you want to collect the stuff it is a good idea to keep it in an airtight case with some silica gel. Otherwise your anhydrite specimen might revert to gypsum!

Flint: Sedimentary Quartz

Flint is a variety of a sedimentary rock called chert. Chert is composed primarily of micro-crystalline quartz and can be many colors, but when it contains a lot of fossilized algae it becomes black and is called “flint.” Technically any chert that is black or toffee-colored is called “flint.”
Flint is formed when calcite in limestone is replaced by silica, thus flint is often found with limestone or even contained within a limestone shell (This can be seen in the first picture) In Kentucky’s Mammoth Cave large nodules of the stuff are found poking out of the cave’s limestone walls! Flint has a glassy texture and breaks with a conchoidal fracture like obsidian. Flint is amorphous, meaning that it has no distinct shape, but it is often found as lumps. Many years ago flint filled the Y and T-shaped tunnels of ancient creatures, so casts of this form are sometimes discovered.
Because of its conchoidal fracture, flint can be used to make bladed tools such as arrowheads and has been used in this manner since ancient times. Flint produces sparks when struck with carbon-steel and has been used as a fire-starter. Flint was also used with flintlock guns. The hammers of these firearms held a piece of flint and when the trigger was pulled the flint struck a steel plate, which ignited the powder and caused the gun to fire.
Many books have listed England as a source of flint. Germany and Denmark are also considered sources. Flint Ridge, Ohio contains the rock and I have found good specimens in central Kentucky. Based on what I understand, flint can be found in many other places, but I cannot name any other specific sources.

Aegirine: An Uncommon Common-Mineral

Aegirine is common, in fact it is a component in some types of rock, but good crystals are significantly rarer. These crystallize in the monoclinic system and look like tiny models of the Washington Monument. Aegirine is black, but it bears tinges of red, green or brown. Its vitreous luster gives it the shimmer that we associate with glass and quartz.
As is the case with many minerals aegirine was once known by a different name because it was not well-understood. Sweden’s famous chemist Jons Jacob Berzelius was the first to unlock the secrets of the mineral’s chemistry some time in the early 1800s. Once he had identified its chemical structure he changed the name from acmite to aegirine, naming it after the Norse sea-god Aegir. It was suggested that he name the new mineral after him self, but he refused the honor and for his humility I tip my hat to him.
As I said before aegirine is a common mineral, but collectable specimens are only found in a few places. These include: Malawi, Russia’s Kola Peninsula, Norway, Greenland, and Arkansas.
I hope that you’ve enjoyed this post about aegirine. For a mineral with no technological uses nor any applications in jewelry it is quite an interesting stone.

Marcasite: The Brother of Pyrite

Marcasite and pyrite have a great deal in common. In fact they are each composed of the same chemical! Read on and learn more about this fascinating mineral--the brother of pyrite.
Marcasite is a polymorph of the chemical iron sulfide, just like pyrite. (You can read more about polymorphs in my post Polymorphism: One Chemical Many Minerals published on this blog May 6, 2011) Marcasite is of a similar pale-yellow color and it shines with a metallic luster as does pyrite. It gets its name from the Arabic word for pyrite and jewelers still call pyrite “marcasite.”
If there are these many similarities between the two minerals then how on earth can anyone tell them apart? Well, it has been difficult. It wasn’t until the 1800s that anyone could differentiate the two. There are some characteristics that are different, though. For starters marcasite has a different crystal shape than pyrite. Pyrite crystals are cubic whereas marcasite’s are orthorhombic. Now, when its crystals twin they can look like spears. Marcasite can also form in bladed, tabular, prismatic, massive, botryoidal, nodular, and stalactitic habits as well as “cockscombs” which look like the combs on chickens’ heads. Unless a marcasite specimen has very well-formed crystals it can still be a challenge to differentiate it from pyrite. Fortunately marcasite’s streak is a little different (read more about the streak test in my Nov. 1, 2010 post Pyrite the Imposter) Marcasite’s streak is greenish brown whereas pyrite’s is greenish black. Marcasite also exhibit’s a sulfur smell, which, as far as I know, pyrite does not.
There is one property that marcasite exhibits that pyrite does not, which I find rather unfortunate. Marcasite is unstable and will decay in the air. How fast it decays depends a lot upon how pure the sample is and how it is stored and handled. I keep mine in an air-tight container with a moisture-absorber, but so far no one has found a way to keep them from decaying indefinitely.
Marcasite is found in such places as: the Czech Republic, France, Greece, Belgium, Russia, Peru, Mexico, Peru, Japan, and the U.S. states of Michigan, Oklahoma, Wisconsin, Pennsylvania, Arkansas, and Illinois.
I hope that you enjoyed today’s post about pyrite’s brother marcasite. Next time I plan to write about marcasite’s unfortunate decaying problem.

Mimetite: Poisonous Contents

I had known about mimetite for quite some time before I came to own a piece of it and even after I acquired one it was a while before I learned much about it. I hope you will enjoy today’s post, which shares what I have learned about the mineral mimetite.
I have discovered that mimetite gets its name from the Greek word for ‘imitator’ because it resembles another mineral called pyromorphite. It is formed when galena and other lead-bearing minerals are exposed to the air and alter over time, so it is not surprising that it often occurs with galena and anglesite.
My mimetite specimen is yellow, but I’ve learned that the mineral can also be brown or green in color. Perfect mimetite crystals are slender hexagonal prisms, but they are very rare. Mimetite is usually found as cauliflower-shaped crusts or growing in a botryoidal habit (masses shaped like bunches of grapes) Mimetite crystals can also be barrel-shaped in which case they are called ‘campylite’.
I have not read anything that would suggest mimetite is especially hazardous, but I would advise the collector to use caution when handling the mineral as it contains lead and arsenic in its chemical makeup.
Mimetite is found in such places as: the Czech Republic, Germany, as well as in the Mexican states of Durango, Sonora and Chihuahua. It is also found in Arizona.
I had a lot of fun learning about mimetite and I hope that you have, too!

Obsidain: GlassFrom the Volcano, Part Four: Is It a Rock or a Mineral?

For the time being I am finished talking about obsidian. For my final obsidian post I would like to answer a question that some may be wondering: is obsidian a rock or a mineral?
To be honest I’m not exactly sure. To be classified as a mineral a substance must be an in-organic, naturally occurring, homogenous solid that has a definite chemical composition and a crystal structure. A rock is a natural aggregation (mixture) of minerals. Generally a rock is a mixture of more than one mineral, but sometimes it is composed of only one such as marble, which is made entirely of calcite. Obsidian is an inorganic homogenous solid, but it has no crystal structure and an indefinite chemical formula. One piece that I read described obsidian as a mineraloid, which is a mineral-like substance that does not have a crystal structure, and is of an indefinite chemical composition. This very same piece, however, also described obsidian as an igneous rock, a label that obsidian is also able to wear as it is a mixture of minerals. Most other books that I’ve read seem to call obsidian a rock, but it is still a difficult call to make.

Obsidain--Glass From the Volcano: Part 3, Location! Location! Location!

Since obsidian is of volcanic origin it could be found wherever there is or has been volcanic activity. Some important sources are: Arizona, Utah, New Mexico, Hawaii, Oregon, Japan, Mexico, the Indonesian island of Java, Guatemala, Iceland, Ecuador, and Italy’s Lipari Islands.
Another famous source of obsidian is Yellowstone National Park in the state of Wyoming. Many scientists assume that there was a volcanic eruption there many years ago, so it makes sense that one can find obsidian there. (There is actually a large outcrop of the stone in the park called “Obsidian Cliff.”) I myself found two nice pieces of obsidian in Yellowstone when my family and I went there last year. One was a nice glassy, black, translucent chip about the size of a quarter and the other was a black, nearly opaque, broken lump with beautiful spheres of white minerals in it, one of which was exposed by a break. Unfortunately, I couldn’t add these to my collection because it is illegal to remove minerals from a national park! I was, however, able to photograph them and I’ve used the photo of the little chip as this post’s picture.
Next week I will make my final obsidian post (for now, anyway) which explores obsidian’s curious properties.

Obsidian: Glass From the Volcano--Part 2

Well, I’ve kept all of you waiting long enough to read about obsidian’s uses. Here is the long-awaited post which describes how this odd volcanic glass was used in the past and how it is used today.
Obsidian is arguably one of the most useful stones in all of Creation. Like quartz and flint, obsidian breaks with a conchoidal fracture (which means that its chips look like conch shells) Anything that breaks with a conchoidal fracture can be flaked into very sharp blades (this is called 'knapping') Obsidian is no exception. In fact, obsidian has the sharpest cutting edge of any natural material! In the past people have used obsidian to make such bladed tools as arrowheads, knife blades, spear heads, saws, and axe heads. Obsidian is actually still used to make these implements by hobbyists (my self included) and for use in ocular and neurosurgeries. The reason that obsidian is used in surgery is because of the fact that it can be given a finer edge than stainless steel and therefore it leaves finer cuts that heal faster and leave less scar tissue behind.
Obsidian has been used to make jewelry for thousands of years and is still polished and cut for this purpose today. Another use for obsidian that is no longer around today, but nevertheless still fascinating is as a material for making mirrors. This was done by the Aztecs and the people of Ancient Greece. I’m not exactly sure how they made mirrors out of obsidian, but I do find the idea an intriguing one!
I hope you enjoyed today’s belated post. The next will discuss the locations in which obsidian is found.

I'm Back

Hello everyone. It's been more than a year since my last post and for that I appologize. A lot of other things have come up and I let this slide onto the backburner. I will be adding more interesting things in the near future!