Sunstone Gemstones - Feldspar type of gems - Also known as Goldstone
Introduction
This is a gemstone that is favored by many for a variety of reasons. The most fantastic feature of this gemstone is the fact that it has a marvelous and glittery property that is known as aventurescence. The gemstone has many names and is sometimes known as Oligoclase, Heliote and Aventurine feldspar. The aventurescence of this stone is very striking and the effect is said to be caused by either Goethite or Hematite. However the Oregon sunstone owes this glittery feature to the presence of copper within the crystal. Sunstone derives its name from the fact that it is usually reddish brown in color, but it can also be found in yellow, gray or green.
For thousands of year past, this is a gemstone that had graced a number of jewelry pieces and it has a rich history and folklore. The Vikings, were said to have used this gemstone in aiding them in navigating the high seas. The early settlers in America used to grind the gemstone and use it as medicine. This is generally a member of the feldspar family of gemstones and is very similar to Labradorite. This is a gemstone that is normally cut as a cabochon since it is opaque and sometimes translucent in nature. It is very rare that you get a transparent sunstone to be cut into facets. This is quite a hard gemstone and has a value of 6 to 6.5 on the Mohs scale. The gemstone is mainly found in the United States of America, India, Canada and Norway.
Moonstone and Sunstone both belong to the feldspars family of gemstone and that is the only resemblance that they have. The moonstone has wonderful varieties which are mainly soft and gentle in their adularescent nature, while the sunstone can be said to be warm to fiery, and has a very distinct and lively nature which is known as aventurescence.
Basically, aventurescence is a feature whereby the gemstone seems to have a metallic and sparkly luster which is brought about by the flat and reflective inclusions found in the crystal. The sunstone is mainly yellow, brown or orange, but now all of them have the aventurescent nature. The aventurescence depends largely on the size of the inclusions. Small ones will bring about a gold or red sheen on the surface of the stone, irrespective of the main color. The large inclusions are the ones that form attractive and fiery reflections of light that bring about this feature. The inclusions in sunstone, once again can be caused by many minerals including hematite and copper.
It is not all feldspars that are called sunstone which come from the same side of this family of feldspars. Plagioclase and Oligoclase are also feldspars, but they have a triclinic crystal system. Oligoclase sunstone has a monoclinic crystal system.
The name of the gemstone was attributed to it simply because of the way it looks and has no reference to its chemical nature. If there is any aventurescence in the gemstone, then specialists in the gemstone world also call it an aventurine feldspar. There are the aventurine feldspars that come from India which have a reddish-brown body and have a very sunny glitter. These are some of the most popular sunstones ever.
The Oregon sunstone
There is a mine which is found in Oregon, from whence several varieties of sunstone are found. There is an increased supply of the gemstone in this particular mine, and this has increased the supply of the gemstone to the general public. Since there are several types of sunstone in existence, and are unique to the high-desert area which is found in South Oregon, they are clearly named as the all-American gemstones.
The Oregon sunstone is a special variety which gets its aventurescent nature from the presence of copper inclusions in the crystal. It is generally colorless, but there are other colors in existence, and these are pink, which has a brilliant aventurescence and pale yellow. Others are green, blue-green, red and orange.
The transparent red, green and orange varieties come from the Plush and Ponderosa mines in Oregon. The sunstone variety that has a vivid red color is also known as the spinel red sunstone and it has a very vivid body color and is also quite hard. This is one variety that gives the red spinel and the ruby a run for their money.
All the gemstones that come from Oregon have a very special sheen, which is brought about by the copper within, and the aventurescence is still visible even when the inclusions are small, unlike in other cases where small inclusions do not exhibit this character. There are Oregon sunstones that have two or three colors at the same time, just the same way that some tourmalines do. It is very rare when you may find Oregon sunstones which have a pleochroic nature. Today, the deep red, and deep green varieties and also some which have two or three intense colors, are considered to be the finest ever.
Since this sunstone variety is never treated, it is also called the all-natural and all-American sunstone. This is a special advertising technique that has been adopted by dealers in Oregon sunstone in order to attract the attention of potential buyers.
In the year 2004, you could find Oregon sunstone selling at about $10 to $30 for wholesale in 3 to 5 carats specimens. However these same sunstones would go for about $350 to $1,000 for those that were extra fine in quality.
The Oregon sunstones were formed out of the mineral known as feldspars, and this was due to the action of volcanos. The crystals of feldspar can be found in many places on the planet. However, only the pink schiller, red, green, and multicolored varieties come from Oregon.
For those which have other colors, the pink schiller is the most popular. The next one is the red one. However, the green and the multicolored Oregon sunstones are extremely rare. For those with an exceptional rarity, the blue-green variety take the price, since they are very, very rare and beautiful as well.
In 1987, the Oregon Sunstone was declared as the official gemstone of Oregon. It has a hardness value of about 6.2 to 7.5 on the Mohs scale, making it exceptional for setting in jewelry. When you put your money in the Oregon sunstone, you are making a wise investment, and it is for these reason that they are also livingly called the Oregon Diamonds.
The Oregon sunstone costs a lot to bring from the ground, since a ton of raw material may only have a single pound of sunstone in it, and even then, only a fraction will actually be gems quality sunstone. The scarcity if this wonderful gemstone and the unpredictable mining process and availability of the colors is what makes it very hard to market it to the general public. When you look at the perspective of mass wholesalers and retailers, you see that they would rather deal with a more predictable gemstone, so that when they build the demand, through rigorous marketing, they have a ready supply to sell. There is a marked hesitance in ordering for sunstone, since they are not sure of the quantities and qualities that will be available once it is mined.
Sunstone is also found in Tanzania, which over the past decade has become a very high producer of a variety of gemstones. Some of the gemstones discovered here in the recent past include the tanzanite, spinel, tsavorite red ruby sapphire and Chrysoberyl. Recently, the aventurine feldspar, which is also a sunstone was discovered there and it has hit the market with a bang. This feldspar has a lot of hematite and copper in the crystals, and it can be found in transparent and translucent clarity values. The multi-colored variety is the one that has created a big sensation in the market.
How to cut and polish the Oregon sunstone gemstone
This is generally a gemstone that pleases most lapidaries. It is quite hard, with a value of 6.2 to 7.5, and it is quite easy to cut and polish. It is quite good for quick production of gemstones and jewelry pieces. Sunstone has a critical cutting angle of about 41 degrees, and there are specialists who sometimes say that it should be cut at 43 degrees and abo; the optimal cutting angle is about 45 degrees.
The orientation of the cleavage does not bring any trouble to the lapidaries. The easiest way to go about this is to determine the orientation of the schiller and color and simply follow it. The schiller is considered first, before the cleavage is. However, should it be necessary to consider the cleavage angle of a cetin stone, then it should be at about 7 to 10 degrees away from the table. At certain times, the facets that are closer to the cleavage plane will feel a bit softer, and they will be easier to cut from those of their neighbors. When this occurs the cutter has to use a light touch and should polish the stone accordingly.
The orientation for color in the sunstone will depend on the occurrence of the color, which is in a bull´s eye pattern in most of these gemstones. This is a spot of intense color, which is them followed by a clear or straw-colored edge. It is best that the cutter focus the cut at the center of the stone since this will bring out most of the color at the pavilion. This is an orientation that will force the light to enter the stone at the crown and have it reflected through the deep color zone, before it later leaves the stone thereby maximizing the color. However, if you are dealing with a large stone, then you can place the main color just below and parallel to the table.
The orientation of the schiller requires the evaluating the amount that is present in the rough. This requires that the cutter remember that a faceted stone sparkles by refracting and transmitting the light, while the schiller works best by reflecting the light. Once a schiller reflects a ray of light, then this light is no longer available to the rest of the stone for refracting and transmitting. Again, when the schiller is hit by light from behind, it will bring out a shadow and affect the brilliance.
Sunstone may not be a mainstream gemstone, but the sparkling and warm colors will attract people who love innovative jewelry designs. There was a marked increase in the purchase of sunstone in the 1990s, made by some of the leading designers in the industry. There was one that stands out; it weighed 13 carats and was made out of the reddish orange Oregon sunstone, and it came in third place in the combination division of the 1997 American Gem Trade Association´s Cutting Edge Awards. The current market for this wonderful gemstone can be classified as a specialized one, which is favored among top jewelry designers, connoisseurs, tourists and carvers who are found in the Oregon desert, many times, looking for the precious stone. There is an imitation sunstone which is made of pure glass which has copper crystals added to it, and it is called Goldstone.
A short profile of sunstone gemstones
Although it is thought that the rock family of minerals that is called quartz, which has wonderful gemstones such as black onyx and amethyst is the most common in the whole world, but geologists say that this is not so. They say that the feldspar are the most common minerals on the planet, and whose main gemstones are moonstone and sunstone.
However, whether this is a true fact or not, one can say that feldspars are the most common minerals when you look at the average American household. These are found in ground and clay form in many items that are used in the home for cleaning and decorating. If you have fire bricks in the house, or have soft scrubbing compounds for cleaning in the kitchen, then you have feldspars in your home.
The mines who work the mines in Oregon would like for the Oregon sunstone to be added among the minerals that are common in the home. There are two factors that seem to favor this notion, and these are the quantity and quality that is found there. The Oregon sunstones are usually red and orange in color, and these are the most popular colors. They also have the widest range of the fantastic green colors available too. There are times when they will come across rough material that does not have inclusions at all, and these are cut into facets. You notice that the sunstones that come from India, which is another major source of the gemstone, are cut unto cabochons since they are not very clear.
Heliolite and Sunstone are some of the names that are given to the Oregon feldspars. However, sunstone is the common name that is used when referring to either of the two varieties. Nobody knows how sunstone came to get its name, with some saying that it is due to the fact that it has the color of the sun, and others saying that it is because of the reddish inclusions which make the stone look like it has a covering of metal-flake paint.
However, the most probable reason may be the metal-flake paint appearance, and this is the reason why the gemstone is also said to be a phenomenon stone. The millions of small copper platelets or hematite particles found in the Oregon and Indian sunstones are most responsible for this classification. These inclusions bring about the reflection of light within the stone, and the resultant play of colors is knows as schiller, a word from the German language that is usually associated with the moonstone having a blue or white sheen on the surface; Labradorescence, which is vivid play of colors attributed to feldspars, or iridescence, which simply means the intermingling of brilliant colors.
However, none of these terms can correctly be used to describe the Oregon sunstone. This is a gemstone that does not necessarily display colors, but instead displays a lot of light. Therefore, the correct term that can be used on this variety is aventurescence. This is a word that comes from the Italian language Aventura which simply means chance. This is an irony in itself since there are some mineralogists who refer to the sunstone as the aventurine feldspar. This word aventurine, refers to the sparkling phenomenon; aventurescence.
Upon realizing that most collectors are not very familiar with the Oregon sunstone, experts have studies thousands if sunstones so as to come up with one single story for marketing purposes. The colors range from red to orange, and others have a plum, raspberry, peach and salmon color. The Indian sunstones have strong yellow and golden colors.
When it comes to faceted gemstones, the Oregon sunstone stands out from all the others. Only 5 percent of the sunstone that comes from the Ponderosa Mine is actually facetted. Most of them have an orange and red color, but there are rare occurrences of the green and clue varieties too.
