Saturday, July 30, 2011

Coral is the Gemstone of the Week

Coral is the gemstone of the week, even though it is not a mineral gemstone, but rather a macrobiotic substance formed from small plant like sea life. Most commonly found in red, pink (angel skin) and white, coral also occurs naturally in blue, orange, violet, red, gold and black. The ox-blood red coral is the color that is most valued for jewelry. Coral that comes from Italy is said to be the best quality.

The basic composition of coral is calcium carbonate with a little magnesium and a trace of iron. It is semi-translucent to opaque and is relatively soft. On the Moh scale, the hardness is 3.5 to4. Coral is actually the skeletal remains of marine polyps. The polyps are surrounded by a fleshy skin and secrete a substance that allows the coral to grow. Over the centuries, the names that different corals are given have been based a lot upon their shapes. Bamboo coral resembles bamboo shoots, brain coral, the human brain, mushroom coral, mushrooms, sponge coral, sponges and so on.

Coral is found in many parts of the world. The best quality red coral is found in the Mediterranean Sea, the the Red Sea and the sea around Japan. Pink coral, or angel skin coral, is found in limited amounts in the Mediterranean area, China, India and Japan. The pink Hawaiian coral is also quite well known. Blue coral is found in the sea around the Philippines. Black coral is found around Hawaii, Australia, the West coast of Africa and parts of the Mediterranean. There is not much demand for the blue and black kinds, so the price for those is not as high as the prices for red and pink coral.

The most common enhancement for coral is dying. This is done to either change color or to make the color more uniform. Sometimes it is bleached. Coral is often filled and coated with an epoxy substance to fill cracks and cavities.  

Many species of coral are endangered, but not all of it. Some coral, like bamboo and sponge coral are farm grown specifically for the market place. They are fast growing corals that are harvested in shallow water farms which makes them a sustainable resource. Global warming, pollution and harvesting for aquariums are the major causes of coral depletion.
Another form of coral that is popular for jewelry is Fossil Coral. Since that is a whole different variety, I will use another post to talk about that.

It is believed that coral can aid in the healing of lung, stomach and heart problems and help with circulation issues. It is also said that it helps in the development of courage, initiative and vitality.  

Mushroom coral and Bamboo coral


Wednesday, July 20, 2011

Aventurine is the Gemstone of the Week

The gemstone for this week is Aventurine, a member of the quartz family that is found in a variety of colors. It can be translucent or opaque, and the presence of mineral inclusions give it a shimmering effect called aventurescence. Colors range from a creamy green, to a medium green, peach, orange,yellow, brown and blue. Chrome bearing fuchite, (a type of mica) is the classic inclusion and gives the stone a silvery green or blue sheen. Oranges and brown get their coloring from hematite or goethite. The orange and reddish orange Aventurine is often mistaken for Sunstone and the greenish variety for Jade or Amazonite. Besides being used in jewelry, Aventurine is often used for ornamental purposes like vases, figurines and bowls. On the Moh scale, it has a hardness of 6.5.
The name Aventurine comes from the Italian for “a ventura” which means “by chance”. Most of the green and blue green Aventurine comes from India. Creamy white, gray and orange stones often come from Chile, Spain and Russia. The main markets for this stone are landscaping and building stone, monuments, figurines and jewelry.
Legend says that Aventurine is an all purpose healer, used to develop confidence, reduce stress, and improve prosperity. It has long been used as a talisman and is a popular stone for gamblers. An ancient Tibetan legend says that Aventurine can be used to reduce near sightedness and increase the wearer's creativity. Many believe it can bring about inner peace and calm a troubled spirit.

          Orange Aventurine

     Green Aventurine

Monday, July 11, 2011

Ruby is the Gemstone of the Week

Ruby is the birthstone for July and is the gemstone of the week. Rubies are the most famous red gemstone. Ruby is the red variety of the mineral corundum (aluminum oxide), which technically makes it a red Sapphire since Sapphires are the other mineral/gemstone made from corundum. Since Rubies have such a special allure and historical significance, they have always been classified as a seperate gemstone and never as a Sapphire. The red color is determined by the prescence of the element chromiun. The name, Ruby, comes from the Latin, “ruber”, meaning red. Pigeon Blood red is the most valuable color in Rubies. The finest Ruby color is described as being a vivid medium dark toned red. These are found in Myanmar (formerly Burma) and have a bluish hue to them. The first laser was created using a Ruby.
On the Moh scale, Rubies have a hardness of 9. Among natural gemstones, only moissanite and diamonds are harder. All natural Rubies have imperfectons in them, including color impurities and rutile needles known as “silk”. These needle inclusions help distinguish natural Rubies from simulated or synthetic stones. The color is determined by the amount of chromium and iron in the stone. There are also Rubies that are called Star Rubies. These stones have rutile needles in them that form stars, also called asterism. Stones like this are cut into cabochons, while other Rubies are often faceted.
Almost 90% of the Rubies on the market today have undergone heat treatment ,which is the most common form of enhancement. This dissovles the silk inside and improves the color. These heat treatments are done with temperatures around 1800C or 3300F. Another treatment that has been used in the last several years is lead glass filling. It's a four step process that fills the fractures inside the stone with lead glass, making a previously unsuitable stone suitable for jewelry. It's possible to find high quality gemstones that have not been enhanced.

Rubies are found in Myanmar, Thailand, although production is declining there, Madagascar, Tanzania, India, Afghanistan, Cambodia, Viet Nam and Kenya. The color varies depending on the country of origin.
Famous Rubies include the 167 carat Edwards Ruby on display in the British 
Museum of Natural History, the 138.7 Rosser Reeves Star Ruby, which is in the Smithsonian, and the 100 carat DeLong Star Ruby on display in New York at the Natural History Museum. Rubies have long been a part of royal insignia and other famous jewelry. Some famous large Rubies in the British Crown Jewels, the Black Prince's Ruby and the Timur Ruby are actually spinels. Up until the 19th century, spinels were belived to be Rubies.

There are many beliefs and legends about this gemstone. Rubies have long been considered a stone of love and passion. It is believed that the person who wears a good quality Ruby will have a life of peace and harmony, protected against danger and blessed with good health. It is also believed that the stone aids in the healing of peptic ulcers, depression, fever and gout.

This photo is the Rosser Reeves Star Ruby.

Tuesday, July 5, 2011

Flourite is the Gemstone of the Week

Flourite has been nicknamed “the most colorful mineral in the world.” It comes in a range of sparkling colors from purple, blue, green, yellow, colorless, brown, pink, black to reddish orange. Intermediate pastel colors can be found in between the colors in some stones, also. Some Flourite is a single color, but most have multiple colors arranged in bands. A now scarce variety of purple blue Flourite, known as Blue John, is found in one of the oldest known localities for the gemstone, Castleton, Derbyshire, England. It is still mined there, but only a few tons per year.
Flourite was first called flourspar. Flourite derives from the Latin noun, “fluo” meaning stream or flow. Flourspar comes from the German “flusse” meaning stream and “spaerstan” meaning spear. It is a relatively soft stone, a 4 on the Moh scale. It is composed of calcium flouride.
Flourite is a widely occuring mineral found in large deposits in many areas of the world. Deposits are found in China, Austria, Germany, Switzerland, England, Norway, Mexico, Kenya, and Ontario, Newfoundland, and Labrador, in Canada. In the United States, deposits have been found in Missouri, Oklahoma, Illinois, Kentucky, Colorado, New Mexico, Ohio, New Hampshire, New York, Alaska, and Texas. In 1965, Flourite was named the state mineral of Illinois since at that time, Illinois was the largest Flourite producing state in the U.S.. In 1995, the last Illinois mine was closed.
Besides being used as a gemstone, Flourite also has industrial uses depending on which of the three purity grades it is. Metallurgical grade Flourite, the lowest grade has been used a flux to lower the melting point of raw materials used in steel production. Ceramic 
grade, the middle level of purity, is used in making opalescent glass, enamels and cookware. The highest grade, which is 97% pure, is acid grade Flourite which is used to make hydorgen flouride and hydorflouric acid by decomposing the Flourite with sulfuric acid. There is also synthetically grown Flourite which is used instead of glass in some high grade telescopes and camera elements.
When it come to the metaphysical aspect of Flourite, it is believed that Flourite opens pathways of the brain to higher dimensions of light, increases alertness and mental activity and helps in grasping complex and abstract concepts. It is also thought to bring in objectivity and concise thoughts, action and behavior.

These photos show some of the different colors, and the banding of Flourite.