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Roger Weller, geology instructor

wellerr@cochise.edu

AMETHYST

Interesting Facts about a Pretty Purple Gemstone

By Jesika Cline   Spring 2007

 

 

www.cs.cmu.edu

 

What is it?

 

          Amethyst is a variety of quartz known for its beautiful purple color. In fact, when translated from other languages such as the Dutch word “amethist,” the meaning is “violet”. Throughout history many people across cultures and generations have been in awe of its beauty. Amethyst is a very common gemstone and can be found in or on a wide variety of rocks, including granite rock formations and agate geodes. It is used to make jewelry in the form of cut stones, beads and calves, and is also admired in natural form, ranging in size from very tiny singular crystals to over 6 ft tall geodes.

Its chemical make-up is SiO2 (Silicon Dioxide). With such a simple composition the cause for its coloration has been debated greatly by scientists.  Recently its purple color has been attributed to the presence of manganese in quartz and the intensity of the color has been determined to be affected by the amount of iron present. An interesting property of amethyst which also affects its coloration is its response to heat. If heated to temperatures as low as 250 degrees Fahrenheit the crystals will turn to a yellowish brown colored citrine. This phenomenon is why often Citrine is referred to as “burnt amethyst.”

http://www.wegnercrystalmines.com/22/imagesmf/MAR%202006/GIANT%20AMETHYST%20&%20PAT.jpg

 

Rock Stats

Picture of Amethyst

Chemical Makeup:

Color: Various shades of purple; sometimes bluish, reddish or brownish

 

Index of refraction: 1.5-1.6

 

Birefringence: 0.01

 

Mohr’s Scale Hardness: 7

 

Cleavage: none

 

Crystal system: Tetrahedral

 

Pleochroic: no

 

Specific Gravity 6.5

 

 

Si02 molecule formation                   

http://www.3dchem.com/molecules.asp?ID=184#

 

Where is it Found?

 

Amethyst can be found all over the world, but varies in size, color and clarity based on it surroundings. Below is a list of places where it can be found and which types of crystals can be found in each location. A * symbol indicates a location with exceptional specimens.

 

USA

-Arizona- reddish hue, varying sizes

-Texas- light to dark, varying sizes

-Maine- Dark colored druzy. (Druzy means tiny quartz crystals found on the surface of or within another stone)

-North Carolina- Blue tinged druzy

*-South Carolina- medium to dark varying in size

-Pennsylvania- Brown tinged druzy

 

Mexico

-Vera Cruz- Pale average crystals

*-Guerrero- Dark average crystals

 

Brazil

*-Mina Gerais, Rio Grande de Sul & Bahaia- Light to medium colored ranging in size, some quite large crystals

*-Marba- Pale to medium color large crystals

                                                                                                          http://www.jewelinfo4u.com/images/amethyst_mines_map.gif

Canada

-Thunder Bay- reddish coloration druzy crystals

 

Uruguay –Dark to medium color druzy

 

Africa- Unattractive color but large and clear

 

Italy- Pale varying in size crystals

 

Germany- Light druzy

 

Russia

*-Ural Mountains- Dark clear large crystals                                                                                                                                                             http://www.umanitoba.ca/geoscience/faculty/arc/PICTURES/AMETHYST.JPG

 

 

What is it Worth?

 

          Although amethyst is a very desirable hardness for a gemstone, ranking closely to garnet 6.5-7.5, tourmaline at 7-7.5 and topaz at 8, its abundance is what limits its ability to become tremendously expensive. It is so readily available in stores around the world that even rather nice specimens are relatively cheap in comparison to their other gem counterparts. An example of this is easily demonstrated.

This 3.69carats garnet (pictured on the left), advertised on http://www.mineralminers.com is priced at $221.40 where as this 11.56 carats amethyst (pictured on the right), from the same website is only $127.16. Both stones are fantastic specimens, but because garnets are not as easily accessible, they are able to be sold for a much higher price. Overall, the amethyst’s monetary value is direct reflection of supply and demand.

If looking for a simple necklace and earrings set of a medium quality color and clarity, there are sets available for as inexpensive as twenty bucks. However exceedingly nice specimens in the form of large cut stones and enormous geodes can be upwards of several thousand dollars. Size, color, and clarity are what determine the quality of a piece of amethyst, with darker, clearer, larger specimens being of the highest value.

 

http://petrifinds.us/store/images/BrazilianGeodes_AmethystCathedral.jpg

 

Magical Powers and Other Fun Facts

 

          One of amethyst’s most interesting claims to fame is its supposed ability to prevent drunkenness. The word amethyst comes from the Greek word amethystos meaning “not drunk.” People were so confident of the stone’s ability to battle alcoholism that frequently cups or chalices were fashioned out of the stone to drink wine from in order to take the ill affects out of the beverage.

          More interesting mystical abilities include protection from seduction (possibly related to its defense against alcohol), protection for crops against locusts, quelling excessive stomach acid, and bringing good fortune in war and for the ill. Yet more abilities include sharpening the wit, turning away evil thoughts, making the barren woman able to bear children and giving knowledge of the future in dreams.

Amethyst is also known for being a symbol of God adorned on religious garments worn by Jewish religious leaders and in the Roman Catholic religion ranking members traditionally wear rings set with a large amethyst as part of their office. It is also the state gemstone for South Carolina. But perhaps it’s most well known attribute is being the birthstone for the month of February.

 

Conclusion

 

In conclusion, amethyst is a wonderful gemstone. Its brilliant color accompanied by its abundance and low cost makes it an affordable treasure for rock hounds everywhere. Although it may not really prevent people from becoming intoxicated or sharpen their wit for that matter, it is still very fetching as a neck ornament or piece of interior decoration. Whatever form of admiration necessary amethyst is able to oblige.

 

 

Works Cited

http://www.answers.com/topic/amethyst

http://www.bernardine.com/gemstones/drusy.htm

http://en.wikipedia.org/wiki/Amethyst

http://www.galleries.com/minerals/gemstone/amethyst/amethyst.htm

http://www.gemland.com/arizonagems.htm

 http://www.gemstone.org/gem-by-gem/english/amethyst.html

http://www.jewelrysupplier.com/2_amethyst/amethyst_properties.htm

http://www.scstatehouse.net/studentpage/gem.htm