Druzy

 Today I thought I’d like to talk about a stone that I think is rather interesting…it has a number of spellings for the word…druzy, drusy, druse, drusies…but they all are known to be in reference to the tiny quartz crystals that form either on the surface, or in crevices of the stone.  This makes for a very unique appearance.   Over the years when I’ve offered these kinds of stones people have showed a great deal of interest with the pieces selling quickly.

Emerald Green Drusy Dioptase Crystal Cluster,Druse crystals on matrix. from Altyn-tyube, Kazakhstan

Most of my information will be in point form but the way these stones are formed requires more detailed description…silica dissolved in running ground water seeps into porous rocks, if it cooks rapidly, which often happens, it causes tiny crystals either on the surface of the rock or in and small cavities, when this is on top of previously deposited minerals this is called a “drusy”. 

Blue Drusy Chrysocolla Gem Silica, Chrysocolla covered with druzy Quartz Crystals

Amethyst Crystal Cluster Purple Phantom Crystals, Violet Bi Color Amethyst, from the La Sirena Silver Mine, Guanajuato, Mexico

  
    It can be found in/on the following:

• Chrysacolla, chalcedony, cobalto-calcite, malachite, psilomelane, carnelian, uvarovite, pyrite, hematite,
•  Agate druzy is titanium coated in a vacuum chamber, a permanent metal coating, in shades of iridescent white, dark or bright blue
• Most common is quartz druzy
• Garnet, calcite and dolomite along with a few other minerals can be drusy coatings
• Mined in the United States, Mexico, parts of South American, Africa and Europe
• The popularity has increased in the last 10 years or so
• The druzy often has the appearance of sugar crystals, is very bright and sparkly
• Natural druzy is either transparent, beige or tan crystals
• Colored druzy is synthetically enhanced
• Druzy can also be dyed
• have been on occasion coated with metals such as 24 carat gold
• Most druzy are found in cabochon…these stones are flat one side and generally set in bezels
• Druzy is not a delicate item but due to the shape and texture of these stones they are susceptible to damage it banged on a hard surface.
• Size and shape of druzy is determined by the stone itself, generally a free formed shape
• Comparatively the cost is less than some of the more expensive gemstones; of course this depends on the cut, size and color.

Uvarovite (Green Garnet) Druzy Crystals on Chromite Matrix

I will continue to offer this beautiful gemstone this coming season…
As always leave a comment on my blog or send me an email at hjcote11@gmail.com

Have a great week!

Cheers…

***I would like to thank MaryanneFender of Fender Minerals for allowing me to use her gorgeous photos of Druzy…

Information Sources:

http://en.wikipedia.org/wiki/Druse_%28geology%29

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

http://www.ehow.com/about_6533173_druzy-crystal-definition.html

http://www.ehow.com/about_5031843_drusy-quartz.html
http://www.ehow.com/about_6606347_titanium-drusy_.html

Tourmaline

This week I decided to do a gemstone post…after checking the Etsy shop of Maryanne Fender to see what colorful stones she had in stock I chose Tourmaline.  Part of the reason for this choice is, I don’t think many people are familiar with this gem…

I’ve not used this semi-precious stone much in the last 6 years as the faceted tourmaline is rather expensive, but I’ve always liked faceted tourmaline, as it has a gorgeous sparkle and shine to it.  Opaque tourmaline is lacking the vibrancy of the faceted gem…at least that is how I feel about the gem.

This is one of the few gemstones which come in a multitude of colors…an Egyptian legend states during its long journey from the center of the earth the tourmaline passed a rainbow, taking on all the rainbows colors, which is why the tourmaline is called the “gemstone of the rainbow”.     

Black Tourmaline Schorl Crystal, Minas Gerais, Brazil

The word Tourmaline comes from “tura mali”, which roughly translates to “stone with mixed colors”.   You certainly can find tourmaline in a mixture of colors; ranging from reds to greens, from blue to yellow, black, pink, often a gem will be two or more colors…some gems will even change color with the light. 

 

Schorl Black Tourmaline,

 Bold Radiating Starburst Pattern in Schist, 

Vadito Schist, Picuris Mining District, 

Taos County, New Mexico

This gem has many names to correspond with all the different colors…

• Intense red tourmaline is known as “rubellite” but only if the color doesn’t change with the light…if it changes it is then a pink tourmaline
• Blue tourmaline are called “indigolites”
• Yellowish-brown to dark brown tourmalines “dravites”
• Black tourmaline is called “schorl”
• Green tourmaline is called “verdelite”, except when the green is due to chromium particles, then it is called “chrome tourmaline”
• Stones with two colors are called “bi-colored” ones with more than two colors are called “multicolored” tourmaline.
• I’m sure you’ve heard of or see the “watermelon” tourmaline stone…the center is red/pink with white, then green surrounding it.  This coloring is a rare natural occurrence.   

 

Watermelon Tourmaline Crystal Gem Rough Slice

Tourmaline has been found in Brazil, Sri Lanka, south & south west Africa, Nigeria, Zimbabwe, Kenya, Tanzania, Mozambique, Madagascar, Pakistan, Afghanistan, USA, mainly in California and Maine.  There are many gemstone deposits with finds of tourmaline but not always great color or quality…which is why there is such a large price difference in these gems.  

Pink Green Tourmaline 

"bubble gum pink"

 Crystal with a 

top-hat of albite,

Paprok, Nuristan,

 Kunar, Afghanistan

 

                             

   Dark green tourmaline,

Cruzeiro Mine,

 Minas Gerais, Brazil

Facts of interest:

• Is dichroic…changes color
• Largest known crystal is 192 carats, with a value of over $25 million
• The pattern for tourmaline is hexagonal and grows in long prisms, often with several prisms growing together, which adds to the beauty and price of the gem.
• Blue and green tourmaline can be heated to enhance the color of the gem, which then makes the cost higher.
• Used to promote artistic and creativity…maybe I should wear something made from this gem?
• Like most gems, it is believed by those working in alternative medicine this stone has healing powers for both physical and mental issues.
• Black tourmaline is the most abundant color found. 
• This gem is a 7 to 7.5 on the hardness scale and breaks easily so wear rings with care, as hitting the stone against anything hard could crack or break the gem.
• Do not clean in an ultrasonic cleaner…when heated this gem attracts dust so try to keep from heat.
• Something I found unusual for a gemstone is the tourmaline can be electrically charged by heating and cooling or simply by applying pressure by rubbing the stone…apparently scientists are interested in this unique quality as well.  
• This gemstone is used in pressure gauges…
• One of two October birthstones.

For anyone not familiar with this colorful gem it truly is a beautiful stone…especially when it is strung together with a rainbow effect.  Hopefully I’ve created a little interest in this striking gem…I may even see what I can find…if I do I’ll post a photo.

Don’t forget questions and comments are welcome…

hjcote11@gmail.com

Cheers

• http://www.facebook.com/heather.cote.5
• http://www.facebook.com/pages/Azure-Accessories/353012479650?ref=hl

 Use of photos courtesy of:

Special thanks to Maryanne Fender of Fender Minerals for allowing the use of their gorgeous gemstones…

Information Source:

• http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp14-95/tourmaline.html
• http://www.gemstone.org/index.php?option=com_content&view=article&id=110:sapphire&catid=1:gem-by-gem&Itemid=14
• http://en.wikipedia.org/wiki/Tourmaline
• http://www.ehow.com/about_6375364_interesting-tourmaline.html
• http://www.ehow.com/facts_5178805_tourmaline-stone_.html

Birthstone of the Month ~ August ~ Peridot (Olivine)

This striking green stone is also called Chrysolite and in the mineralogy world it is known as a variety of stone from the mineral family Olivine. It is thought the name Peridot comes from the Arabic word faridat which means "gem".   This beauty only comes in various shades of green, pale yellowish green, olive green, bottle green or a vibrant apple green, which is the most sought after, any shades of brown decrease the value of the stone.  In Pakistan, near the Afghan border you will find large Kashmir peridot stones which are the best for cutting, possessing intense striking color, which of course makes them expensive.  Most of the worlds Peridot, 80 to 95%, come from the San Carlos Reservation in Arizona, being mined by the Native Americans…finer quality gems come from Myanmar (formaerly Burma) and Egypt.  Other locations where peridot can be found are Australia, Brazil, China, South Africa, Hawaii, New Mexico and Zaire. 

Peridot Crystals in a Volcanic Bomb from Kilbourne Hole, Dona Ana Country, New Mexico

80mm x 60mm 200 grams

I'm including the definitions of igneous and metamorphic rocks as I think it helps to understand what these words mean...
Metamorphic Rocks
"The American Heritage Science Dictionary: 1. relating to metamorphosis. 2. Geology: Relating to rocks that have undergone metamorphism. Metamorphic rocks are formed when igneous, sedimentary, or other metamorphic rocks undergo a physical change due to extreme heat and pressure. These changes often produce folded layers or banding in the rocks, and they can also cause pockets of precious minerals to form. The folds and banding can be produced by incomplete segregation of minerals during re-crystallization, or they can be inherited from pre-existing beds in sedimentary rocks or pre-existing layers in igneous rocks. The precious minerals can form as the result of re-crystallization when the rocks undergoing metamorphism are subjected to changes in pressure and temperature.

  Natural Peridot Crystal from Sapat, Pakistan
17 mm x 12 mm, .65 inches x .5 inches

“Igneous: "
adjective
1. Geology...produced under conditions involving intense heat, as rocks of volcanic origin, or rocks crystallized from molten magma. 2. of, pertaining to, or characteristics of fire.
Intrusive Igneous Rock: forms beneath the surface of the volcano
Extrusive Igneous Rock: forms on the surface volcano"
Peridot, formed in the earth’s mantle, 20 to 55 miles inside a volcano…they are found in extrusive igneous rock forms, as a result of magma reaching the surface of the volcano, either from eruption, or cracks, fissures or as lava or ash.  It can also form in metamorphic rocks.   In other words it is found in the rocks formed by volcanoes.  The striking green color of the peridot comes from chemical composition of the stone (iron) itself and not from some other sources such as impurities.   Peridot is transparent but often includes some form of inclusion, they appear as spots or lines, and are naturally occurring deposits of such things as silica glass, biotite mica, and small crystals of pyrope garnet and spinal.   While lovely, the peridot is not a brilliant stone, it may have the appearance of glass or even look greasy…the stone may have a cat's eye or star effect but this is extremely rare.  Treatments, such as oiling or polymer filler may be used to improve the look of the stone, by decreasing the visibility of flaws. Care must be taken with the peridot as it is tends to burst under pressure, it is sensitive to heat and is not resistant to acids...so keep away from household cleaners, steam, hair spray, etc.

Faceted Peridot Gemstone, 6 mm x 4 mm 1.5 carats 

Stones of Interest:

• A 319ct peridot found on the island of Zabargad is now in the Smithsonian Institution in Washington DC.
• Cut stones from a meteorite that fell in 1749 in eastern Siberia are now in Russia.
• 192.75 carat peridot stone belonging to the Czar is in the Diamond Registry in Moscow

Information of Interest:

• Historians wonder if the gems worn by Cleopatra were actually peridot and not emeralds…
• Some wear this stone as they believe it brings success, peace and good luck
• It is the gift for the 16^th wedding anniversary.
• It is one of the few stones that comes in one color only
• In ancient Egypt on an island called Zeberget mining for peridot was done at night as it was said the gemstone couldn’t be seen well during the day. 
• I’ve seen the phonetic spelling as per-i-doe and per-i-dot…so not sure which is correct, I do think both are accepted.
• Associated with light
• Generally a transparent gem
• Ancient records document peridot being mined back as far as 1500 B.C.
• While it can be…this stone is generally not treated or enhanced
• Relatively inexpensive in price
• All be it rare, peridot have also been found in meteors  
• Avoid ultrasonic cleaners, mild soap and water will clean this stone
• Cracks easily so be gentle with it…

 Don’t forget…send any questions or comments to the following email address…

hjcote11@gmail.com

Cheers

Information courtesy of:

Special thanks to Maryanne Fender of Fender Minerals for allowing the use of their gorgeous gemstones…the Volcanic Bomb was found in Kilbourne Hole, New Mexico.

   

·         Gemstones of the World,Walter Schumann, Third Edition, Sterling Publishing Co.

·         The Jeweler's Directory of Gemstones, Judith Crowe, Firefly Books, 2006

·         "igneous." dictionary.com Unabridged (v 1.1). Random House, Inc. 21 Aug. 2008. dictionary.com http://dictionary.reference.com/browse/igneous

·         "Metamorphic" The American Heritage® Science Dictionary. Houghton Mifflin Company.  21 Aug. 2008. dictionary.com   http://dictionary.reference.com/browse/metamorphic

·         International Colored Gemstone Association: http://www.gemstone.org/index.php?option=com_content&view=article&id=101:sapphire&catid=1:gem-by-gem&Itemid=14

·         http://www.mineralgallery.co.za/peridot.htm

·         GIA:  http://www.gia.edu/research-resources/library/featured-gemstones/peridot/index.html

·         http://nevada-outback-gems.com/Encyclopedia_pages/Peridot.htm

The Birthstone for the month of July is the stunning Ruby!!

Along with the sapphire, emerald and diamond, the ruby is considered a precious stone. The ruby and its sister stone the Sapphire are a member of the corundum species...the word corundum means “very hard mineral used as an abrasive”.   You might be surprised to know the only difference between the ruby and the sapphire is the color.  

Rubies are found in Afghanistan, Australia, Cambodia, India, Kenya, Pakistan (Kashmir), Russian, United States, (North Carolina), Greenland and Vietnam, with some of the most important finds in Myanmar (formerly Burma), Tanzania, Thailand, and Sri Lanka. 

Deep Red Natural Ruby Crystal and Natural Faceted Ruby Cut StoneA composite terminated crystal from Madagascar and a Burmese (Myanmar) Faceted Stone, both natural

The ruby ranges in color from pink to blood-red in color.  The most desirable red (Latin – ruber) being blood red with a touch of blue, which is called “pigeon’s blood”.  The presence of chromium provides the red and the presence of iron explains any brown tones.  The color of the ruby will vary within each deposit making it difficult to determine the location where found by looking at the gem. When you hear “Burma ruby” or Siam ruby” more often this is referring to the quality not the source location of the gem.

The color is often uneven with stripes and spots throughout the gem, all natural rubies have imperfections including impurities and inclusions such as the needle like rutile, known as “silk” which the Gemologist uses to determine the real ruby from the synthetic ruby.  Rubies with a 3 or 6-point star are cut into cabochons to show the star effect. The presence of chromium provides the red and the presence of iron explains any brown tones.

Ruby Pyrite Marble Matrix Natural Mineral Specimenfrom Ganesh, Hunza Valley, PakistanThis marble containing corundum (the mineralogical name for ruby and saphhire) runs all the way from Afghanistan to Burma (Myanmar).

The ruby in its rough form is dull and greasy, as are most gems, but it is said once the gem is cut “the luster can approach that of the diamond “.  Since the 1960’s it has become common for the ruby to be treated with heat to improve the color, as a result the cost of a natural untreated Burmese ruby of 10ct would be on par with a natural diamond!    Having said that the ruby is one of the most expensive gems, with large ones worth more than diamonds, which is why they are often used for royalty/wealthy jewelry and insignia.

  

Ruby in Fuchsite (green mica) Puff Heart CabochonPuff Pillow cabochonBoth sides polishedStone mined and cut in India 

The ruby is hard with only the diamond harder, but it lacks cleavage*, as a result the ruby is brittle therefore, cutting and setting the stone must be done carefully.

Cleavage*: “Crystal can break along the lines of weakness related to the atomic structure (cleavage) in such a way that a flat surface which is called a cleavage plane is left. Where the break is not related to the fracture, the resulting surface will not be flat or smooth.  Fracture may be described as uneven, splintery.  Cleavage and fracture affect the strength of a gemstone as well as how easy it can be worked/cut/shaped”.

I admit I was surprised to find the natural, untreated ruby is such a valuable gem.  

Some interesting information:

• The ruby is used to celebrate the 15^th and 40^th wedding anniversary.
• It is used in ancient times for bad health and to protect against misfortune.
• Placed on building to ensure good fortune to the building.

 

Don’t hesitate to contact me with any questions or requests!

     

Watch for healing aspects of semi and semi precious stones coming soon…

Cheers

• Many thanks to the  photographer who so generously allowed her work to be used in my feature!
• Maryanne Fender, Fender Minerals
  

• Gemstones of the World, Walter Schumann,Third Addition,Sterling Publishing Co.Inc.
• The Jeweler's Directory of Gemstones, Judith Crowe, Firefly Books, 2006