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About Joe Norris
Expertise
I am an economic geologist. An economic geologist does mineral evaluations and appraisals of mineral or mining properties. I can tell you if your deposit has value - remember that a mineral deposit, no matter how good, only has value when mined. Any value assigned to a mineral deposit, in the ground, is only the speculative value that deposit.

Experience
I have been a economic geologist for most of my 35 year career. Although I have done work in perhaps 45 states and numerious countries much of my work has been in Appalachian coal, intermountain west gold and silver, and Arizona uranium.

Organizations
Past President of the Virginia Section of the American Institute of Professional Geologists and a certified geologist in twelve states.

Education/Credentials
BS Degree from Eastern Kentucky University. Work on MS Degree @ Eastern Kentucky University, Colorad School of Mines & Marshall University Numerious short courses on the value of mineral deposits and how to value same. Also several short courses dealing with the different types of geologic processes; sedimentary, igneous, metamorphic along with the mineral associated with each.

You are here: Experts > Science > Geology > Geology > obsidian

Geology - obsidian

Expert: Joe Norris - 10/30/2009

Question
I am preparing a homework regarding obsidian rocks.An I would like to know if the obsidian rocks are used in nowadays in industry.
Can you help me?
Thank you in advance.

Answer
Obisidian was used by Aztecs for the sharp points of their weapons, mirrors, masks, and for ear ornaments. They called the material Iztli and surnamed it Teotetl meaning 'Devine stone'. They named it so because of its diverse uses, one of which was the 'smoking morrow', which was used by the Mayan priests for scrying to predict the future. Obsidian has been used by people throughout the history in areas where volcanic activity occurs or has occured in the past.

Obsidian was widely distributed throughout Mesoamerica by trade. Its importance to Mesoamerican societies has been compared to the value and importance of steel to modern civilization. However, archaeology provides varied evidence of the individual value placed on obsidian. For example during the Preclassic period, obsidian was a rare item in the lowland areas, found predominantly in elite and ritual contexts. In many Maya excavations evidence of obsidian is likewise found most frequently in privileged settings. As the Late Classic period progressed, obsidian became increasingly accessible to the lower classes of Maya civilization. Nevertheless, the Maya elite continued to remain in possession of the more prestigious Teotihuacan green obsidian.

In the Teotihuacan culture obsidian was perhaps traded at a loss of human effort in transport across long distances. The profit from the trade lay in prestigious elite items received in return. Obsidian has both been seen as a key element to Teotihuacan's rise to power and as a side trade element that simply augmented their already developing wealth. Obsidian is a part of many elite items such as valuable ear-spools, but these obsidian ear-spools have been discovered in exclusively non-elite settings. Thus the value of obsidian can be considered highly variable. It was an important trade item, but found in both elite and common settings, unlike many items whose ownership was confined to the elite. Finally, there is no indication that obsidian was used as a currency in Mesoamerica.

Nowadays...

Nowadays, Obsidian is most widely used as gem stones and ornamental stones and it is thought that obsidian has magical powers as well. Obsidian's ornamental purposes as a gemstone are well documented. It possesses the property of presenting a different appearance according to the manner in which it is cut. When cut in one direction it is a beautiful jet black; when cut across another direction it is glistening gray. "Apache tears" are small rounded obsidian nuggets embedded within a grayish-white perlite matrix.

Obsidian has also been used in cardiac surgery, as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels, with the edge of the blade being only about 3 nanometres wide. Even the sharpest metal knife has a jagged, irregular blade when viewed under a strong enough microscope. When examined under an electron microscope an obsidian blade is still smooth and even. One study found that obsidian produced narrower scars, fewer inflammatory cells, and less granulation tissue in a group of rats.

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