Stone of the Week - Malachite

Malachite is considered a carbonate of copper, and is often seen with Azurite (another copper carbonate). Malachite commonly forms by the oxidation of copper – hence it is often found near copper deposits. It can also form when deposited by metoric water in sandstones. The word malachite comes from the Greek word molochitis, meaning "mallow-green stone", presumably due to the fact that it is not a hard mineral and thus easily worked with.

Malachite can occur as acicular crystals (left), as its common botryoidal form (center), and often found with azurite (right).

Malachite has a brilliant green color, of varying shades, but occurs only as green – no other color. Usually it is seen as alternating bands of light and green, in what are called botryoidal masses. Botryoidal means that it forms in spherical aggregations, giving it a bumpy or nodular look. Malachite can occur in a variety of other forms, including fibrous, stalagmitic, or even as acicular crystals (pointed or needle like); it can also be found in large masses with no distinct form.

Malachite is available in many styles for jewelry work.

Malachite was often worn by the Greeks and Romans as a form of protection against evil spirits. Malachite was also once used as a pigment for green paint until replaced with a synthetic version. It is more often valued for its decorative appeal, and was very popular with the Russian Czars and was used to form the columns St. Issacs in Leningrad. Tsar Nicholas II gifted "The Tazza" to August Heckscher in 1910, later given to the Linda Hall Library located in Missouri. Today it is a popular gemstone to use in jewelry, as it is ‘soft’ enough to cut, but not so fragile that it would be difficult to use in jewelry work.

The Tazza at the Linda Hall Library reading room, Missouri

Care and Cleaning: While it is not recommended to soak malachite in water for extended periods, a soft damp cloth should be sufficient to clean up any of your pieces. It is also not recommended to expose it to heat nor acids.

If you have a stone you would like to know about, please feel free to leave a request in the comments section. Have a mystery stone? Leave a link in the comments to a picture of it, and it may be featured as a part of this series!


Malachite Facts:
Chemical composition: Cu2CO3(OH)2
Color: Green
Habit: Commonly botryoidal, also massive, stalagmitic, fibrous, or acicular crystals
Fracture: Uneven or subconchoidal
Cleavage: Good
Luster: Vitreous/dull to silky
Hardness: 3.5-4
Specific Gravity: 3.9-4
Streak: Green
Occurrence: Worldwide; large quantities in the Ural Mountains


References
A Guide to Rocks and Fossils by B. Busbey III, R. R. Coenraads, P. Willis, and D. Roots. Published 2002 by Fog City Press. ISBN: 1877019518

Rocks, Minerals, & Fossils of the World by C. Pellant and R. Phillips. Published 1990 by Little, Brown and Co. ISBN: 0316697966

Wikipedia – Malachite. http://en.wikipedia.org/wiki/Malachite

Wikipedia – Tazza. http://en.wikipedia.org/wiki/Tazza

Stone of the Week - Amethyst

Amethyst is one of my favorite stones. Well ok, I have a lot of favorite stones – we’ll say this is my favorite purple stone :)

Amethyst in rough form.

Amethyst is actually a type of quartz that has impurities in it that make it this pretty purple color – in the case of amethyst, the impurities are ferric iron. Amethyst can actually change color if exposed to heat – usually to yellow and brown colors, hence sometimes called ‘burnt amethyst’. Sometimes also found with white quartz, and a banded version of alternating white quartz and purple amethyst is refered to as ‘Chevron Amethyst’. The most valued shade of amethyst is a bluish-purple variety called ‘Deep Russian’.

An egg shaped and large crystal of amethyst.

Amethyst is often associated with granites and pegmatites, and can be found in a variety of shapes. The most spectacular is the pointed hexagonal prisms or crystals. A special kind has many tiny crystals that you can’t really see any one crystal, and is commonly sold as ‘fairy amethyst’ though the technical term for it is drusy. It can also be found in geodes, as double terminated crystals (points on both ends), and massive forms.

Amethyst can occur as very pretty crystals. The sample on the right is often called 'fairy amethyst' or drusy amethyst.

Amethyst is the birthstone for Feburary. In metaphysical terms, amethyst is believed to get rid of negativity. Because of the origin of the word Amethyst from the Greek word for ‘not drunken’, many believe that the ancient Greeks and Romans believed it could guard against intoxication, and thus used it to create goblets to hold wine. However a more likely interpretation is that they called the stone amethyst since its color resembled that of wine.

Amethyst is sold in a variety of shapes and sizes for jewelry, including tumbled beads, chips, and freeform stones.

How to tell it from other purple stones: The most other common stone that amethyst is confused with is flourite. Flourite usually appears as a vareity of colors and rarely is sold as just purple. One of the main differences between these two is the hardness - amethyst has a hardness of 7, while flourite has a hardness of just 4 on the Mohs Hardness scale. To tell hardness use objects with a variety of hardnesses to see if the stone can scratch the item or if it scratches the stone (obviously you don't want to do this with your good stones or in a place thats easily seen!). For instance glass has a hardness of 5.5, so flourite wouldn't scratch it but amethsyt would; a coin is 3.5 so both would scratch a coin; a steel knife is 6.5 so would scratch flourite and 'shouldn't' scratch amethyst but it might just a little as impurities in quartz can lower the hardness slightly. Another difference is that flourite occurs as cubic while amethyst is hexagonal (six sides).

Care and Cleaning: Amethyst is not soluble in water, so a damp cloth is safe to use to clean it. To keep it from changing color or lightening, it should be kept away from windows or other sources of heat.


If you have a stone you would like to know about, please feel free to leave a request in the comments section. Have a mystery stone? Leave a link in the comments to a picture of it, and it may be featured as a part of this series!


Amethyst Facts:
Chemical composition: SiO2, ferric iron impurities
Color: Shades of purple
Habit: Commonly 6 sided (hexagonal) prisms, also massive
Fracture: Uneven and conchoidal
Cleavage: None
Luster: Vitreous
Hardness: 7
Specific Gravity: 2.65
Streak: White
Occurrence: Worldwide


References
A Guide to Rocks and Fossils by B. Busbey III, R. R. Coenraads, P. Willis, and D. Roots. Published 2002 by Fog City Press. ISBN: 1877019518

Rocks, Minerals, & Fossils of the World by C. Pellant and R. Phillips. Published 1990 by Little, Brown and Co. ISBN: 0316697966

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

Stone of the Week - Quartz

For the first in my series about stones, I figured Quartz is a good place to start since there is such a variety of it. Quartz is the most abundant mineral on the Earth's surface, due to its resistance to weathering. When it does weather, it is still often in pieces or grains that end up in igneous, metamorphic, and sedimentary rocks. Quartz is a versatile stone, used for many things besides jewelry, such as lab equipment and industry. The ancient Romans cut quartz into round balls that were polished and carried around by wealth Romans to cool their hands during the summer months. One weighting 106 pounds is currently on display at the National Museum in Washington D.C.

Quartz is often seen as crystal points, but can occur in other forms such as this egg shaped quartz.

Quartz comes in many forms, usually as hexagonal prisms, although these are often imperfect. It can also form as large massive bodies. Quartz crystals can grow to enormous sizes – one in Brazil weighed 40 tons, while another in Kazakhstan was 70 tons. Quartz crystals can be singularly terminated (has one point) or as a double terminated crystal (two points on either end) which is less common. It is also common in geodes, which are round rock formed by bands of minerals (often some type of quartz) accumulating on top on each other, and can have a void in the center with crystals.

Examples of Quartz inside geodes

The variety of color in quartz is due to impurities within the crystal, and a number of these have different names. Chalcedony is a cryptocrystalline (microcrystalline) form of quartz with very small crystals – hence you don’t get the hexagonal crystals but often appears as smooth and banded. Other cryptocrystalline quartz includes agate (multicolor, banded), onyx (like agate with straight bands, multi color or black), carnelian (reddish orange), jasper (opaque, multi-color), aventurine (often with shimmering micas, commonly green), prase (green), plasma (dark green), heliotrope or bloodstone (like plasma but with dark red spots), sard (reddish-brown), and moss agate (has dendritic patterns of manganese).

Other quartz varieties include amethyst, which is a purple color due to the presence of manganese or ferric iron, and is perhaps the most valuable form of quartz as a gemstone. Rose quartz gets its color from traces of manganese or titanium, and can lose its pink color when heated. Smoky quartz is a dark brown color, is caused by irradiation; a very dark brown /black type is also known as morion. Citrine is commonly a pretty yellow or orange color due to inclusions of iron hydrates. Tiger’s eye is a fibrous form of quartz that is typically a yellow-brown color, but with the addition of impurities can appear as other colors.

A variety of quartz, including amethyst, jasper, citrine, carnelian, agate, rose quartz, double terminated quartz, and rutilated quartz.

Quartz can also be rutilated, having golden rutile through it, as seen in the photo above (tumbled yellow/white piece) or tourmalated which has black tourmaline in it. This occurs in quartz veins, where the quartz forms around the rutile or tourmaline.

A number of these varieties will be featured later for a more in depth look. There will also be a review of terminology used in the 'stone facts' and how to test stones. Amethyst will be the next in my series, so check back to learn more about this beautiful purple gemstone.


If you have a stone you would like to know about, please feel free to leave a request in the comments section. Have a mystery stone? Leave a link in the comments to a picture of it, and it may be featured as a part of this series!



Quartz Facts:
Chemical composition: SiO2
Color: Most common white/clear, but occurs in many colors
Habit: Commonly 6 sided (hexagonal) prisms, also massive
Fracture: Uneven and conchoidal
Cleavage: None
Luster: Vitreous
Hardness: 7
Specific Gravity: 2.65
Streak: White
Occurrence: Worldwide


References
A Guide to Rocks and Fossils by B. Busbey III, R. R. Coenraads, P. Willis, and D. Roots. Published 2002 by Fog City Press. ISBN: 1877019518

Rocks, Minerals, & Fossils of the World by C. Pellant and R. Phillips. Published 1990 by Little, Brown and Co. ISBN: 0316697966

Wikipedia – Quartz. http://en.wikipedia.org/wiki/Quartz

Hello World!

So this is my new blog, and I thought for the first post it'd be appropriate to tell a little about myself.

I design my own jewelry, which is currently available at http://bijoutery.etsy.com I've been a member of Etsy for several months, but haven't really become a seller until about October this year. I'm excited I've had a few sales so far, and can only wait to see how the next year goes! If you've never been to Etsy you must go! It's like ebay for art, but so much better!

I love working with a lot of different media - wire, stones, pearls, crystals, all of it. I've only dabbled in working with metal some and wire wrapping, and hope to get more time to do that over christamas break.

My styles really vary. I do seem to prefer more of a 'nature/natural' look, using leather, pearls and stone a lot. I especially love celtic and native american art. I suppose in part because of my belief style - I can technically be called a pagan simply by the definition of pagan if nothing else. But I don't identify myself with that per se - I have a thing about labels, lol. (Why restrict one's self to being labeled?) But I do have a view that nature and life is sacred and should be something we protect, not destroy.

I'm currently a graduate student at Western Kentucky University working on a MS in Geoscience. I hope to study planetary geology, and planning on a thesis that will compare deltas on both Earth and Mars - but that's all in the early planning stages so we'll see where that goes! I love geology - and it has only helped my love of working with stones in my jewelrywork.

My next post will be the first in a series about different stones, whether they be minerals, rocks, or hey maybe even fossils! So if there is one you'd like to know more about please feel free to leave a request in the comments, or if you have a stone you'd like identified, include a link to a photo of it and maybe it'll be featured on here!

A few other sites to see my stuff:
Flickr - http://www.flickr.com/photos/21429532@N07
My Art Profile - http://www.myartprofile.com/bijoutery