Minerals And Crystals

Classifying minerals can range from simple to very difficult. A mineral can be identified by several physical properties, some of them being sufficient for full identification without equivocation. In other cases, minerals can only be classified by more complex chemical or X-ray diffraction analysis; these methods, however, can be costly and time-consuming.

Physical properties commonly used are:

Crystal structure and habit: A mineral may show good crystal habit or form, or it may be massive, granular or compact with only microscopically visible crystals.

Hardness: the physical hardness of a mineral is usually measured according to the Mohs scale. This scale is relative and goes from 1 to 10. Minerals with a given Mohs hardness can scratch the surface of any mineral that has a lower hardness than itself.

How to Identify Common Minerals
from wikiHow - The How to Manual That You Can Edit

You are panning for gold, and have been sitting there for hours, with no result. Suddenly - there it is! A large, dirty rock with a metallic sheen! Have you struck it rich? You know that Pyrite (Fool's Gold) looks almost exactly like real gold. How do you know that this is real gold?You can find out the answer by studying the mineral's hardness, appearance, luster, streak, clevage, and fracture, as well as other properties such as magnetic attraction. Well, is it gold or not?
Steps

1. Begin by taking a look at the mineral's color. If it is, say, purple, and is kind of crystal shaped, then you can be pretty sure that you have a quartz or an amethyest. Unfortunately, many minerals are one shade or another of brown, and it is difficult to figure out which is which without a more indepth invesgation.
   
2. Examine the mineral and take note of its surface features. Is it bumpy? Smooth? Layered? Kind of crusty feeling? Also, if the color pattern is interesting, as is the case with malachite, you will want to remember that.
   
3. Get out the materials needed for the hardness test (see Things You'll need). Below is a hardness scale. See what your mineral matches.The number is the hardness, followed by the characteristics of a mineral of that hardness and an example
   
   • 1 -- Soft, greasy, flakes of fingers (talc)
     
   • 2 -- Can be scratched by a fingernail (gypsum)
     
   • 3 -- Can be cut easily with a knife or a nail, sctratched by a penny (calcite)
     
   • 4 -- Can be scratched easily by a knife (fluorite)
     
   • 5 -- Can be scratched by a knife with difficulty (apatite)
     
   • 6 -- Can be scratched by a steel file (orthoclase)
     
   • 7 -- Scratches a steel file (quartz)
     
   • 8 -- Scratches quartz (topaz)
     
   • 9 -- Scratches anything lower on the scale (corundum)
     
   • 10 -- Scratches anything lower on the scale (diamond)
     
   
   
4. Next, find out your mineral's luster. Luster is the way a mineral reflects light. It can be metallic like graphite, or nonmetallic like flourite. Nonmetallic minerals can be further classified as dull, pearly, silky, and glassy, as well as other things. You don't have to be a rock expert to figure this out, just think about it for a minute.
   
5. Now for the streak test. It is prehaps the easiest of the tests. You need an unglazed porcelain tile and your mineral. Rub the mineral on the tile, and see what color it leaves behind. Keep in mind that some minerals have no streak, particularly the harder minerals (as they are harder than the streak plate!).
   
6. You can also identify a mineral by the way it breaks. If it breaks along a smooth, flat surface (such as mica), it has cleavage. If your mineral breaks along rough, jagged surfaces, it has fracture.
   
7. Some minerals have other properties. One of the most common is magnestism or magnetic attraction. See if a magnet will stick to your mineral, and see if it picks up iron filings.
   

Tips

• To keep yourself organized, make a list of all minerals that are the same color as yours. Every time you discover something new about your mineral, cross off the minerals that yours could not be. Hopefully, you will end up with only one left - your mineral.
  

Warnings

• Be careful with sharp/rough objects needed for the hardness test.
  

Things You'll Need

• Unglazed porcelain tiles (called Streak plates)
  
• Information about rocks
  
• Magnet
  
• Iron filings (opt.)
  
  • To Test for Hardness
    
    • Copy of the Mohs Scale/hardness scale
      
    • Sample of copper, or a penny
      
    • Sample of quartz
      
    • Iron nail
      
    • Knife
      
    • Steel file
      
    
    
  
  

Related wikiHows

• How to Find a Rock and Gem Club
  
• How to Identify a Real Diamond
  
• How to Identify Wild Flowers
  
• How to Identify a Fake Watch
  
• How to Identify a Bird
  

Article provided by wikiHow, a wiki how-to manual. Please edit this article and find author credits at the original wikiHow article on How to Identify Common Minerals. All content on wikiHow can be shared under a Creative Commons license.

Inorganic matter, if free to take that physical state in which it is most stable, always tends to crystallize. Crystalline rock masses have consolidated from aqueous solution or from molten magma. The vast majority of igneous rocks belong to this group and the degree of crystallization depends primarily on the conditions under which they solidified. Such rocks as granite, which have cooled very slowly and under great pressures, have completely crystallized, but many lavas were poured out at the surface and cooled very rapidly; in this latter group a small amount of amorphous or glassy matter is frequent. Other crystalline rocks, the evaporites such as rock salt, gypsum and some limestones have been deposited from aqueous solution, mostly owing to evaporation in arid climates. Still another group, the metamorphic rocks which includes the marbles, mica-schists and quartzites; are recrystallized, that is to say, they were at first fragmental rocks, like limestone, shale and sandstone and have never been in a molten condition nor entirely in solution. The high temperature and pressure conditions of metamorphism have acted on them erasing their original structures, and inducing recrystallization in the solid state.

Minerals and Rocks Sets

Introduce kids to the joy of mineral and rock collecting. -- Minerals Set comes with 15 different minerals in a compartmented box. Using the included guide, magnifying glass, streak plate and nail kids can test and observe the physical properties of each mineral. -- Rocks Set comes with 5 specimens each of igneous, sedimentary and metamorphic rocks in a compartmented box, activity guide and magnifying glass.

The Field Guide to Rocks & Minerals $20.00

The definitive guide to rocks and minerals, completely updated for the fifth edition, includes 385 color photographs showing rocks, minerals, and geologic formations. Hundreds of minerals are described, with details such as geographic formations. Hundreds of minerals are described, with details such as geographic distribution, physical properties, chemical composition, and crystalline structures.

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4 reproducible activity sheets, a teacher's guide, and 4 sturdy 17" x 22" posters with the following titles: Uses of Rocks and Minerals; Geologists at Work; Identifying Rocks & Minerals; and Igneous, Sedimentary, and Metamorphic Rock.

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This reference collection provides an introduction to the sources of gem minerals for both students and collectors. The specimens are carefully chosen for color, and none have been tumbled. The collection is numbered and supplied in a compartmentalized box, and keyed to an identification guide. -- Please note: Some uncommon specimens are supplied in sizes smaller than 2.5 cm x 2.5 cm. -- Note: collections are subject to change depending upon availability of individual items.

Minerals, Crystals, Fossils Science Kit $28.95

Minerals, Crystals, Fossils EARTH SCIENCE EXPERIMENTS BROUGHT TO YOUR HOME! Grow a salt rock garden, rock candy, and string crystals. Break open a large geode. Identify five unknown minerals using the streak, hardness, magnetic, and acid tests. Study a real plant fossil. Complete this set by making a cast and a mold fossil that will impress any budding scientist. Collection of three kits: Kit 7 Minerals Kit 8 Crystals Kit 9 Fossils Shipping Weight: 1.8 pounds Availability: This item takes 2-3 business days to leave the warehouse plus ship time.

Art Poster Print - Minerals by unknown Print Size: 36 x 24 inches. $22.74

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Southwest Treasure Hunters Gem and Mineral Guide Where and How to Dig Pan and Mine Your Own Gems and Minerals (3rd Edition) (Perfect) $14.99

Southwest Treasure Hunters Gem and Mineral Guide Where and How to Dig Pan and Mine Your Own Gems and Minerals (3rd Edition) Completely updated with the most current information, these guides offer easy-to-use information on the ins and outs of fee-dig mining, complete with locations, costs, tips on technique, entertaining legends and important information on everything from safety kits to where the nearest restrooms are. Included are resources for use in identifying finds, having them made into jewelry, and further pursuing an exciting, and possibly profitable, hobby. In addition, each volume contains maps, black and white photographs and indexes. Topics covered in the books include Equipment and Clothing What you need and where to find it (or how to make it yourself). Mining Techniques Step-by-step instructions on panning for gold, sluicing for gems and other methods. Gem and Mineral Sites Locations of sites with directions and maps, the gems and minerals to be found, hours, fees, and equipment needed. Also includes info on guide services, additional attractions and features at each site, local camping facilities and more. Museums and Mine Tours Where to visit commercial and historical mines, as well as museums with exhibits of gems and minerals (for help in learning what to look for). Special Events and Tourist Information Listings of regional events involving gems and minerals, and sources of general travel and tourism information for every state. Other Features Where to find your birthstone...your anniversary stone...your zodiac stone Index by State Index by GemMineral U.S. State Gems Minerals Chart and more

Flip4Science Rocks & Minerals $74.95

Put todays best practice in teaching science to work in your Earth science centers. Students progress through the 3 stages of Scaffolded Inquiry: Directed, Guided and Full. Kit covers properties of rocks and minerals, mineral crystals, igneous rocks, sedimentary rocks, metamorphic rocks and the rock cycle. Aligned with National Science Education Standards, hands-on Scaffolded Inquiry activities developed by nationally recognized science authors build science literacy skills and prepare students for standardized tests. With a comprehensive Teachers Guide providing step-by-step support and blackline masters, kit is appropriate for teachers with any level of experience in teaching science. For 2-4 students. Grades 3-6. Rocks & Minerals Kit includes: *16-Page double-sided Activity Center Book with photo-illustrated set-up instructions *72-Page Teachers Guide with step-by-step lesson plans and blackline masters *5 Science Journals *Manipulatives and supplies for each activity For a sample lesson, click on the tabs below: Age Range 8-11

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