Friday, January 06, 2012

Garnet, A Gem of Endless Variety

The birthstone of January is Garnet. Garnet has been one of the world's favorite gemstones for centuries. And although gem quality garnets can be among the most beautiful of all gems, they are relatively affordable. There are some varieties, like tsavorite and spessartite that can be very expensive, but most are modestly priced. Though most of us think of garnets as a red gemstone they come in many colors, including orange, green, purple, clear and pink. Some even appear to change color, depending on the type of lighting! Garnets are not actually a single species of gemstone but are a family of gems that share certain physical properties including crystal shape and chemical composition. They are generally grouped into six garnet species, almandine, pyrope, spessartine, grossular, andradite and uvarovite. To complicate matters more, garnets are never just one species, but are a blend of two or more of these.

They are usually named for the species that is most prevalent. A garnet that is described as "pyrope" may actually be 80% pyrope, 15% almandine and 5% spessartine. Some specific blends have also been given names of their own. For example, a garnet that is about 2/3 pyrope and 1/3 almandine is called a Rhodolite. Other names you may encounter for varieties of garnets include demantoid (usually green), malaya ( may be pink or reddish orange) , mandarin (yellow-orange spessartine), hessonite (usually cinnamon brown or yellowish) or tsavorite(green).

Learning, identifying and describing the seemingly endless varieties of garnets is challenging, but they also provide a wide range of prices and colors for every taste. And garnets provide a source of great beauty and endless fascination for gem lovers and mineral collectors as well.

Friday, September 23, 2011

Hubei Turquoise

Hubei Turquoise
Turquoise has been used as a gemstone for thousands of years in many different parts of the world. In the United States we usually associate turquoise with the southwestern part of the country. And in fact, most American turquoise comes from Arizona, New Mexico and Nevada. Turquoise is a stone that forms under just the right conditions in desert areas. It is found in other desert regions throughout the world including Africa, China and the Middle East. Traditionally American turquoise has been the most prized and expensive, however most of the U.S. mines are no longer producing and so the jewelry industry has had to look to other areas for a steady supply of quality material. Many people consider turquoise from Iran to be the finest available, but it is prohibitively expensive. Perhaps the best source these days is China. Chinese turquoise has somehow gotten a bad reputation. Maybe because a lot of low grade or imitation turquoise has come out of China in the past or maybe just because China is associated in many peoples minds with inferior products. But the truth is that some of the finest turquoise in the world is now coming out of China, particularly the Hubei region. Several mines in that area are producing hard, stable turquoise with exquisite color. Much of the material is beautifully spidered with black or dark brown matrix. But Hubei also offers bright blue turquoise with little or no matrix that rivals that of the famous mines in America like "Sleeping Beauty" or Kingman. And best of all, the prices of the Hubei turquoise are still much more reasonably priced. If you love turquoise, you may not have to settle for dyed, treated or imitation products and buying Chinese turquoise doesn't mean that you are settling for second rate gemstones.

Monday, March 21, 2011

Larimar, a Tropical Treasure

Larimar is a beautiful blue gemstone that has been found in only one location on the planet: The Dominican Republic! This may be the only gemstone found in the Carribean Sea and it looks the part! The unique blue shades look very much like the blue waters of the Carribean. Typically Larimar gemstones will be patterned with luscious medium and light blues and some white. Sometimes there are patches of red or some grey or brown matrix. Occasionally Larimar will be slightly greenish. Usually the darker blues are more sought after and more valuable and whiter or greener pieces are less valuable. It has a crystalline structure that is slightly translucent and sometimes has areas that display chatoyance! Chatoyance is a shimmering luster like that seen in Tiger's Eye gemstones.

Larimar is the rare, blue variety of Pectolite. It was apparently first discovered by a Priest in in Dominican Republic in 1916. He requested permission to explore further and possibly to mine the stone but his request was denied and this beautiful stone remained unknown to the rest of the world for another 58 years. In 1974 Miguel Méndez and an American Peace Corps worker named Norman Rilling rediscovered the stone on the beach in the Dominican Provence of Barahona. Natives had from time to time found the stone on the beach and believed that it came from the sea. However, it was discovered that it had actually washed downstream on the Bahoruco River. Exploring up river it was found to have originated from outcroppings on a volcanic mountain overlooking the sea.

Since then Larimar has been mined, usually employing primitive methods and hand tools, by the locals. Larimar jewelry became a very popular item with tourists to the island. The new gemstone was named by Miguel Méndez by combining his daughter's name, Larissa with the Spanish word for sea (mar). Other names that have been used are Dolphin Stone, Love Stone and Atlantis Stone.

Larimar is usually cut into freeform cabochons. The rough is often somewhat crumbly and has some matrix and voids so there is a fair amount of waste when sawing and grinding. Therefore, it is often cut in free form shapes that preserve as much solid material as possible. Finished stones however, take a fine polish and their beauty is stunning. The hardness of Larimar ranges from 4 to 7 on the mohs scale with the darker blue stones usually being harder. So it is roughly the same hardness as turquoise (5-6). The blue color, not found in pectolites from any other location, is as a result of its containing Cobalt.
Larimar is usually set in silver, but sometimes gold. It is often used in much the same way as turquoise and occasionally it is even seen in contemporary Southwest
style jewelry. Larimar gemstones may be a little too soft for everyday wear as a ring but is very popular as a pendant stone or for earrings. Larger pieces make great wire wrap subjects. Larimar offers a shade of blue unavailable in other gemstone material and it adds a tropical feel to any jewelry design

Friday, February 18, 2011

Tiffany Stone

Tiffany Stone is a beautiful and unusual gemstone that is found only in the mountains of Utah. It is also known as "Bertrandite", "Opalized Fluorite" or "Utah Lavender". It is mixture of different colors in swirls, plumes, dendrites and other interesting patterns. Tiffany Stone is composed of predominantly Opalized Fluorite in blues, purples and whites but is often mixed with other minerals such as quartz, chalcedony, dolomite, rhodonite, manganese oxides (blacks), and bertrandite (white, yellow or pink) that contains the mineral beryllium. Specimens with a lot of purple are generally the most sought after. The purple color comes from flourine gases.

Since it only comes from one area in the world, availability is very limited. And only a small percentage of rough material is hard enough and stable enough to cut into gemstones. Most all of the cut cabochons you might find are from old stock.

If you are a jewelry maker looking for something unusual for your next design you should look into Tiffany Stone. If you collect cabochon cut gemstones, you've got to have at least one of these beautiful stones.
View more Tiffany Stone includings lots of matched pairs.

Sunday, November 14, 2010

Chatoyant Pietersite

Pietersite is the name given to a beautiful mineral aggregate that is most often cut into cabochon shapes and makes a great gemstone material. It is closely related to tiger eye and is prized for its chaotic bands and swirls of dark red, gold, brown and sometimes blue. Areas of the stone often display a characteristic known as “chatoyancy”. Chatoyancy is a shimmering, cat's eye effect caused by tiny, fibrous, parallel inclusions.

It is named for Sid Pieters who first discovered it in Namibia in 1962. A slightly different material was later discovered in China and was also classified as Pietesite. I have read that the China mine is closed and so there is no new material coming out of China or Namibia. In any event, supplies are very limited.

Pietersite that contains a lot of blue is the rarest. Dark red is more common. The rich, earthy colors, chatoyant characteristics and striking patterns make it a popular stone year round, but especially in the fall.

Friday, October 08, 2010

Crazy Cool Idocrase

Idocrase is a very interesting mineral. It also can be a very beautiful gemstone! Idocrase also goes by the name Vesuvianite, since it was first discovered on the volcano, Mount Vesuvius! It isn't very well known outside of rockhound and gem collectors circles but as more high grade material is becoming available, especially from East Africa, it is gaining a wider following. Idocrase is usually an opaque dark green. The opaque material has sometimes been used as a simulant or substitute for jade.

The really exciting stuff though, is the bright, translucent pieces! Somewhat included specimens can be cut into beautiful cabochons and cleaner pieces are facet cut. The shade of green varies from slightly yellowish-green to strongly yellowish-green. The color is reminiscent of the popular gemstone peridot.

If you are looking for a green gemstone that is a little out of the ordinary, consider idocrase. It goes well with amethyst and looks great set in silver.

See more at

Tuesday, September 14, 2010

Colorful Gem Chalcedony

Chalcedony is a fairly common stone that has been used for centuries for tools and adornment. It is a form of quartz, called micro-crystaline simply meaning that it is very fine grained. Since it is very hard, it was a popular choice among prehistoric types for making ax heads and weapons. Today it is used primarily as a gemstone.

Although it is a very common stone, you may be unfamiliar with the name chalcedony. By the way, if you've read the word but never heard it pronounced, you might be surprised to learn that it is pronounced cal-SID-nee. The reason you may not have heard much about it before is that different colors of chalcedony are given different,more glamorous sounding names. For instance, I'm sure you've heard of Carnelian. Carnelian is red chalcedony. Onyx is black chalcedony. Green chalcedony is called chrysoprase or chrysophase. Banded chalcedonies are usually called agates. Recently though, some of the other, more exotic colors are getting more attention and used as gemstones. And they are just being called chalcedony. Blue chalcedony has been popular for a while now. And Indonesia yields some gorgeous purple chalcedony that is the color of amethyst as well as some beautiful bright yellow specimens. Nice clean, clear pieces of this purple or yellow material sell for $20 per carat or more.
A lot of chalcedony is dyed or otherwise treated to enhance its color. Most of the carnelian on the market is heat treated or dyed and almost all onyx dyed to make it blacker.. There is also some very pretty, turquoise blue chalcedony being sold that are recieving a diffusion treatment. The important thing is to always ask before you buy. Gemstone treatments are ok as long as they are disclosed. Natural, untreated chalcedony is much more valuable than dyed stones and the color is permanant. The color of treated stones sometimes fades over time. I have seen beautiful blue chalcedony turn grey after being exposed to light for a few months.
Chalcedony is in many ways a perfect gemstone. The colors are bold, striking and wide ranging. Nice specimens have just the right amount of translucency, so they almost look like they are glowing from within. And they are extremely durable! Best of all chalcedony gemstones, for the most part are affordable.