Z is for Zircon – #atozchallenge

Z is for Zircon

Zircon is a naturally occuring mineral formed from the chemical compound zirconium silicate. In its natural state it is clear but impurities give it a range of color. I just love that impurities can make something so beautiful.

Zircons are often used as a substitute for diamonds. It is the only gem that has the same brilliance and fire of a diamond and the untrained eye most likely could not tell the difference. The two major differences are 1) a diamond is a single refractive stone and a zircon is a double refractive stone and 2) a zircon has a Mohs hardness of 7.5 compared to the 10 of a diamond. After a period of time and wear, a zircon could lose the sharpness of the facets which would not occur with a diamond.

The most valuable zircons are either colorless, brown, blue. This specimen in the collection of the Smithsonian is a beautiful blue.

Courtesy of the Smithsonian under Creative Commons Zero (CC0) License

There are a number of industrial uses for zircon. More than half of the zircon mined today  is used in the ceramics industry. There are also chemical derivatives such as zirconia and zirconium. Their uses span the fields of nuclear energy, gas purification, cosmetics, and in the manufacture of cubic zirconias (another diamond substitute).

This post wraps up my first ever A to Z Challenge. It has been fun, but quite a ride. I have learned a lot and I hope you picked up a few things along the way. It has been my pleasure to have you take this journey with me!

 

Y is for Yowah Nut- #atozchallenge

Y is for Yowah Nut

If you are like me, this may be the first time you have heard the term Yowah Nut. I stumbled on this and was so intrigued, I knew I had to write about it. But how do you write about something you know nothing about? You research. You see, a Yowah Nut is not a nut at all. I think you should learn the basics the same way I did. By watching a video.

I hope you watched the video, but if you did not, I will explain. A Yowah Nut is a small nut-like formation of ironstone which encases a Boulder Opal. They were originally discovered in the Yowah Opal field in Queensland Australia. When the stone is sawed into two pieces, the opal (or opal in matrix) is revealed. The following photo is of the specimen shown in the video above.

Courtesy of the Smithsonian under Creative Commons Zero (CC0) License

A sliced Yowah Nut (both sides) can run from $150 (on Ebay) into the tens of thousands (opal auctions) depending on the fire of the opal. I would love to have one, but not at those prices I‘m afraid.

X is for Xaga – #atozchallenge

X is for Xaga

Xaga is a synonym for obsidian a volcanic glass rather than a mineral. The name Xaga is used predominately by California Native Americans.

Most people are familiar with obsidian as the material used to make arrowheads. It is an ideal material because it was easy to chip and once chipped is as sharp as broken glass. It is also a hard material (5.5 on Mohs scale) so it is not likely to shatter on impact which would be an important aspect of an arrowhead.

Commercially, obsidian can be used to make blades that are much sharper than steel. Some scalpels are made of obsidian, however they are not approved for use on humans in the U.S. They are very brittle and break easily if lateral pressure is applied – that could be disastrous. They are used in veterinary medicine and research work.

There is an ongoing project to try and determine how and when people came to the ‘new world’. For years it had been thought  humans crossed over a ‘Bering land bridge’ from Russian into North America. So far there has not been irrefutable proof. Now, however there is hope that by examining obsidian tools routes may be determined. It seems obsidian carries unique fingerprints to specific volcanoes so origins can be traced back. Pretty, cool, eh?

Follow this link for some interesting photos of obsidian at Glass Mountain in California from the American Museum of Natural History in New York City. There are many images and videos online of obsidian lava flows from California and Oregon. They are amazing to see.

Contemporary jewelry is made with obsidian. It has a low toxicity potential, but it does have the potential to cause silicosis if safety measures are not taken.

W is for Williamsite – #atozchallenge

W is for Williamsite

Williamsite is one of the gems from the mineral antigorite, the other being bowenite.

Here is an Interesting segue into American history. Williamsite was named after it’s discoverer Lewis White Williams who accompanied Lt. Ned Beale on the 1857 Camel Expedition. If you are like me and have no idea what that was, head over here to read all about it. It is quite interesting.

Williamsite initially came from the Line Mine that traverses the Pennsylvania and Maryland borders. It is considered one of the many serpentine minerals found in serpentine rocks. Serpentine is not a mineral itself.

The hardness of williamsite measures a 4 on the Mohs scale. It is a translucent green mineral often used as a jade simulant. As with many other minerals, williamsite is often referred to by many other marketing names, like serpentine jade for example.

It has been difficult to find a good photo that I felt okay posting here but I did stumble on this December newsletter from the Mineralogical Society of the District of Columbia. On pages 16-17 there is a reprint of an article from the Bozeman Gem and Mineral Club. The article by Dr. Kenneth Zahn has a great story and photo about williamsite. You can read it here.

V is for Variscite – #atozchallenge

V is for Variscite

Variscite is a somewhat rare mineral of hydrated aluminum phosphate. It is often confused with turquoise both because it can be found in the same locations and because of similarity in color to some types of turquoise.

Variscite has an interesting range of green colors due to the presence of trivalent chromium. While there are no real industrial uses for vasiscite, trivalent chromium is used in chrome plating. It is a much less toxic alternative to use rather than hexavalent chromium which is a known carcinogen.

The term variquoise has been used when an easy determination cannot be made between variscite and turquoise or when both variscite and turquoise coexist in the same rock.

There is no known toxicity with variscite, but as always, be safe when handling any mineral. It is a very soft material (3.5 – 4.5 on the Mohs scale) so it is not a good gemstone choice for rings which are often more susceptible to their environment. Being opaque, it is cut into cabochons or used as carving material.

This specimen from Utah is in the permanent collection at the Smithsonian.

Courtesy of the Smithsonian under Creative Commons Zero (CC0) License