Amethyst

According to Greek mythology, one day Dionysus, the god of wine and song, was angry and vowed to slay the first mortal who crossed his path. That unlucky mortal was Amethyst, a beautiful maiden.

However, Artemis (goddess of virginity and the hunt) intervened and transformed Amethyst into white stone. When Dionysus saw what had happened, he repented and poured wine over the stone, staining the top of it purple. That is why the top of amethyst is purple and the bottom is white.

Amethyst is a brilliant purple or violet variety of quartz, colored by the presence of iron or manganese when the crystals form. Amethyst crystals are hexagonal and can occur as tall prismatic crystals or short, stubby ones, and often have horizontal striations on their sides or faces. As with all varieties of quartz, Amethyst has a hardness of Moh's 7. It is found around the world, notably in Mexico, Brazil, Uruguay, Africa, and Russia.

Amethyst Cathedrals -- popular home decorating and Feng Shui elements -- are actually giant geodes that formed in lava flows. When volcanic material forms, large bubbles are often trapped in the rock. Over millions of years, these bubbles form a coating of minerals from the surrounding soil on the inner surface. If water does not seep through this coating, fine crystals will form that eventually become the masses of crystals we see today. Amethyst Plaques and Bookends are also made from pieces of this interior lining.

With its warm, purple glow, no other purple gemstone can hold a candle to amethyst. However, it's surprisingly affordable! Check out our complete selection of amethyst beads, home décor & metaphysical items, and mineral specimens.

Fossil Preparation

by Marc Behrendt, reprinted from Fossil News

Fossil preparation or cleaning can be done in the home or in a fancy lab. Sometimes all it takes is a toothbrush and water. If the fossil is sturdy, like coral and many brachiopods, this method will remove all the mud and loose matrix. However, if your fossil has any cracks in it, if it is fragile, or if it sits on soft shale, do not try to brush it off with water. Fossils like trilobites, bones and fragile brachiopods will dissolve or fragment. To make something fragile look better, you need a different method to clean your specimen.

Let's assume you have a complete trilobite and would like it cleaned. Part of it is buried in the rock and part is exposed but covered with a thin layer of shale.

To expose the buried portion of the trilobite, miniature pneumatic hammers will be used. Ever so carefully the hammer's pounding chips away tiny fragments of the matrix hiding the trilobite. Usually the matrix touching the trilobite shell pops right off after most of the upper matrix is removed. Great care is taken not to touch the trilobite with the hammer.

Before micro-airhammers were used, fossils were exposed using small steel picks like dentists use (this process is still used in many labs today). The method works very well, as you can see in any older museum collection, but it takes a long, long time to accomplish what an airhammer can do in a short time!

OK, the trilobite has been totally exposed, but is still covered by a thin layer of shale. It is time to pull out the microsandblaster. These instruments, using high air pressure, shoot a tiny regulated amount of powder through a hose and nozzle onto the fossil, eroding the soft rock away while leaving the harder trilobite's shell intact.

With experience or careful experimentation, the air pressure and powder flow are adjusted to remove the matrix from the fossil without "burning" the trilobite's shell away with the rock. All the work is done under a microscope under the watchful eye of the preparator, who is alert for new or previously unnoticed cracks in the shell that will need to be stabilized.

The eyes need special attention. Many kinds of trilobites have the lenses still in the eyes, and these are very fragile. With delicate and precise microsandblasting, the entire eye is cleaned so each lens is perfectly exposed without being damaged!

Finally, the rock itself is spruced up. All the chisel marks from the hammers are ground away using either a combination of airhammer and air abrasive, or with a grinder like a dremel tool. The matrix is shaped into the way it best displays the trilobite. Occasionally, new fossils are discovered under the matrix during this step. These are cleaned up and make nice surprise additions for the piece.

When it's all done, sit back and admire your trilobite. It's no longer grey and covered with rock -- it is a beautiful black or brown color, looking like it will crawl off the rock any moment.

View our large selection of prepared fossils, from $4.00 to $999.00, in our Fossils category. We've also got a fantastic beginners kit!

Field Tools for the Rockhound

Spring is finally here, and that means we're all ready to head out on our rockhounding expeditions! Appropriate tools will make your rockhounding trips easier and safer. You will not, however, need all the tools we list -- pick the ones you need for your particular expedition.

Collecting Tools (marking tools with bright or fluorescent paint helps keep you from losing them)

• Crack hammer (2, 3, or 4 lb): This is for breaking medium-sized rocks and for driving your chisels. Go with the largest hammer you can comfortably handle.
• Crowbar or pry bar: A basic tool every rockhound should have. 22" pry bars are good basic tools, although 30" and larger are needed for really heavy work.
• Hand chisels, wide-ended or pointed: Another basic tool, and you should have a good-quality set of them. Carbide-tipped ones will make your work easier, although they are quite expensive.
• Geologist's pick (hammer/pick): A standard tool used for prying (not hitting rocks unless you want only a small chip) and as a handy guide to scale in photographs! Some manufacturers, such as Estwing, also offer geologist's hammer/chisels, as well as belt sheaths for both tools.
• Sledge hammer (12 to 16 lb) or Mason's hammer (6 to 8 lb): For breaking big rocks. Again, go with the largest you can comfortably handle (and haul). The sledge hammer often is more effective if you cut the handle off at 18".
• Pocket tools: These are used to extract specimens from deep pockets, and will go a long way toward saving your hands. Some possibilities are a commercial pocket tool, an 18" screwdriver, an ice pick, or a modified garden claw.
• Paintbrush/whiskbroom/toothbrush: These are used to clean specimens, to help you evaluate them.
• Tools for fine work: Possibilities are spatulas, surgical knife, palette knife, sieve, dental picks, geologist's trim hammer.
• Other tools: Hoe pick, bricklayer's (splitting) hammer, shovel, trowel.

Specimen Identification

• Field guides: Bring the appropriate field guide for the specimens you are hunting (crystals, fossils, general rocks and minerals, etc.).
• 10x loupe or magnifying glass: A good quality lens is an important aid, particularly for identifying small crystals and fossils.
• Magnet: Meteorites and iron-bearing rocks such as magnetite will attract a small, handheld magnet such as a refrigerator magnet. (A metal detector can be a good investment for a serious collector of meteorites -- or of gold or other metals, for that matter!)
• Vinegar: A few drops of vinegar on your specimen will form bubbles if carbonate is present.
• Streak plate: The color left when a rock is rubbed on a streak plate can help you distinguish between similar-appearing minerals. An unglazed porcelain tile (such as the back of a bathroom tile) can be substituted for a standard streak plate.
• Moh's hardness scale with test items: You can use a regular Moh's hardness kit, or you can use an informal approach. For example, window glass is Moh's 5½ and a steel file is 6½.
• UV lamp (short-wave and/or long-wave) and viewing bag: These are used for identifying fluorescent minerals. A black plastic sheet can be used in lieu of the viewing bag. For more information on this, see our Learn More article on UV Light and Fluorescent Minerals.

You'll find many of these identification tools packaged together in our affordable Basic Mineral Test Kit.

You'll also need some items for transportation of your specimens, navigation and record keeping, and personal/safety equipment (not to mention lunch!). Visit Field Tools for the Rockhound online for a useful checklist.

Geology Word Puzzler

What do we mean when we refer to a rock or mineral's habit? Is the mineral trying to give up smoking?

Habit: (ha-BIT) the characteristic crystal form or combination of forms of a mineral (Dictionary of Geological Terms). This is the shape or form in which a mineral naturally "grows," such as crystalline (quartz), rhombohedral (dolomite), cryptocrystalline (dioptase), acicular (goethite), concretionary (turquoise), tabular (staurolite), or platy (bismuth).

Many minerals may be found in more than one habit, depending on the conditions when they formed. For example, galena may be found in euhedral crystals or in a massive/granular form, and malachite is usually botryoidal (meaning grape-like), but may also be fibrous or stalactitic.

We'd love to hear from you! Have questions or comments about the website, or just want to tell us about your latest rockhounding adventure? Email us at we_rock@mamasminerals.com!

Read about rose quartz, geodes, and identification of rocks and minerals in the Fall 2006 issue of RockZ NewZ

Read about rose quartz, geodes, and identification of rocks and minerals in the Summer 2006 issue of RockZ NewZ

Read about fluorite, fluorescent minerals, and cleaning quartz in the Summer 2005 issue of RockZ NewZ.

Read about vanadinite, building fountains, and identifying meteorites in the Winter 2004 issue of RockZ NewZ.

Read about celestite, pearls, and how to choose the right tumbler in the Fall 2004 issue of RockZ NewZ.

Read about malachite, tumbling grits, and how to pan for gold in the Summer 2004 issue of RockZ NewZ.

Read about galena, petrified wood, and collecting micrometeorites in the last issue of RockZ NewZ, Winter 2003.

Read about iron pyrite, tumbling seaglass, and stony meteorites in the Summer 2003 issue of RockZ NewZ.

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