Sunstone

Also known as "aventurescent feldspar" because some specimens contain light-reflecting inclusions those produce a bright flash.

What is Sunstone?

The name “sunstone” is used for specimens of translucent to transparent feldspar that produce bright metallic flashes when light interacts with tiny plate-like mineral inclusions within the stone. These mineral inclusions usually have a common orientation and light entering the stone reflects from them at a common angle. This produces a flash of light in the eye of the observer who views them at the proper angle. This optical phenomenon is known as “aventurescence”.

The first material to be called sunstone because of its aventurescence was specimens of oligoclase, a plagioclase feldspar. As other types of feldspar with a strong aventurescence

were discovered the name was also applied to them. Labradorite feldspar (another plagioclase) and orthoclase feldspar have both been found with strong aventurescence.

The aventurescent flash of light produce by a sunstone can be observed by three different actions:

moving the stone in the light

moving the position of the light

moving the eye of the observer

Sunstone is also known as “heliolite” and more commonly “aventurescent feldspar”. It is cut into cabochons, beads, and small sculptures. The most transparent pieces are used to produce faceted stones.

Sunstone is popular with innovative jewelry designers and is especially popular in the geographic areas where it is commercially mined. It is not a gemstone that is seen in every jewelry store and many jewelry buyers have never witnessed its aventurescence. However, once a person is given a demonstration of sunstone’s aventurescence, they often want to try it and are fascinated. It is a gemstone that sells best if the jeweler takes a moment to educate the buyer about aventurescence.

Sunstone Localities

Aventurescent feldspar has been found in Australia, Canada, China, Congo, India, Mexico,

Norway, Russia, Sri Lanka, Tanzania, the United States (Oregon, New York, Virginia, Pennsylvania) and other localities.

The most famous sunstone deposits in the United States are located in Oregon. A few of the sunstone deposits in Oregon are large enough to sustain mining operations. They are found in certain basalt flows in Lake County and Harney County. There the sunstone occurs as phenocrysts within the basalt. Some sunstone is produced from the weathered zone above the basalt flows and some is produced from the basalt.

The Oregon basalt flows that contain sunstone are located mainly on public land and many productive or promising areas are held by mining claims. The U.S. Bureau of Land Management has reserved one area in Lake County as a public collecting area where anyone can enter, look for sunstone and keep what they find for personal use. Collectors must follow BLM’s collecting rules and stay off of adjacent lands where mining claims have been registered. A few of the claim owners allow visitors to enter and collect for a fee. [2]

Inclusions that Enhance Desirability?

Inclusions are particles of foreign material in a gemstone. They cause a reduction in the clarity of the stone and usually damage its desirability. However, some inclusions in sunstone can enhance its desirability. These inclusions are perfectly flat, highly reflective and precisely aligned to simultaneously produce a flash of light. Instead of damaging the desirability, these flashes of light usually delight the observer and increase the desirability of the stone.

The inclusions in sunstone are usually tiny plates of copper, hematite or goethite aligned parallel to crystallographic planes within the stone. 

Stones with a small number of inclusions produce a weak aventurescent flash. Those with a greater number produce a stronger flash. Stones with a strong display of this optical

phenomenon surprise people and are highly desirable.

The inclusions in sunstone can be so small that they are not visible to the unaided eye or they can be large enough to be clearly visible. The inclusions are extremely thin. Even though they might be large enough to be clearly seen face-on they are usually too thin to be visible when viewed from the side.

What Color is Sunstone?

Sunstone occurs in a range of colors that begins with colorless and ranges through yellow, orange and red. The color is determined, in part, by the abundance and size of the copper platelets within the stone. The copper platelets impart a pink or reddish color to the stone. Some exceptional stones are deep green or blue in color.

Color can vary within a single stone. Some stones exhibit a color gradient. They might be pink on one side of the stone and the color gradually strengthens to orange on the other side of the stone. Other stones have sharp color changes. These stones might have patches of green in contact with an area of strong red color. Some exceptional stones are pleochroic - their color depends upon the direction of observation.

The value of gem-quality sunstone is determined by its color, transparency and the quality of aventurescence. Colorless and yellow stones are usually the least expensive and values increase through pink, orange and red. Bright red stones, green stones and nice bicolor stones have the highest values. Transparent stones with a nice aventurescence command premium prices.

Sunstone can fit almost any budget. Small cabochons with a pleasant orange color and nice aventurescence can be purchased for under $50. Bright red stones and attractive bicolor stones that have been nicely faceted can sell for over $1000 per carat.

Although aventurescence is what has traditionally defined sunstone, clear, gem-quality plagioclase from Oregon without obvious aventurescence has been sold under the name of “Oregon Sunstone”. [3] Yellow gem-quality plagioclase without obvious aventurescence from Mexico has been sold under the name “Golden Sunstone”. 

Faceted or en Cabochon

Most varieties of gemstones that exhibit an optical phenomenon produced by inclusions (such as the asterism displayed by a star sapphire, the chatoyance of chrysoberyl or the aventurescence of aventurine) are cut en cabochon to best display that phenomenon.

Specimens of sunstone with a nice aventurescence are usually cut en cabochon. Incident light produces a bright glow on a dome-shaped cabochon that is tilted back and forth in the light. When the angle between the observer's eye and the stone is the same as the angle of incident light (but in the opposite direction) the observer sees a bright flash of light. That is when the full reflection from the included platelets is observed.

Transparent "Oregon Sunstone" produces beautiful faceted stones. Faceted sunstone with aventurescence exhibits the beauty of a faceted gem with an optical effect normally seen only in a cabochon.

The “Cut” is Everything

The artisans who cut sunstone must study the stone before they begin work. If the stone is

cut at a random orientation the aventurescence will be less than optimal. The maximum flash and a symmetrical flash in a cabochon is obtained when the stone is cut with the platelets oriented parallel to the top and bottom of the stone. In this orientation the cabochon usually shows maximum color when viewed from directly above and the aventurescence is symmetrical.

Some artisans use sunstone for small carvings and sculptures. Material up to three inches in size has been found and some of these large stones are used for carving. Sunstone beads are also popular. As a bead, sunstone displays aventurescence from both sides of the included copper platelets.

History of Sunstone as a Gemstone

Sunstone has been known for at least a few hundred years. The sunstone deposits of Oregon were discovered by Native Americans who collected the gems, treasured them, traded them widely and sometimes buried their dead with a small bag of stones.

Sunstone deposits near Lake Baikal in Russia were mined in the early 1800s and deposits in southern Norway were mined in the late 1800s. Some stones are still produced in these areas.

In the United States the common use of sunstone by lapidaries began in the early 1900s. At that time Tiffany & Company acquired mining claims near the community of Plush, Oregon. There they opened the first commercial sunstone mine in the United States and produced jewelry with faceted sunstone and sunstone cabochons. They called the clear stones “Plush Diamonds”. Their efforts with sunstone must not have met Tiffany's expectations because they stopped production and sold their claims.

In the early 1980s, new sunstone deposits capable of sustaining commercial mining operations were discovered in Oregon. This was celebrated in 1987 when the Oregon legislature named “Oregon Sunstone” the official state gemstone. This called attention to sunstone within Oregon and to the lapidary community within the United States.

Sunstone Jewelry

When "Oregon Sunstone" was declared the "state gemstone" by the Oregon Legislature, jewelry designers and lapidaries were inspired to work with sunstone and promote it to Oregon residents and tourists. This created a patronage for a gemstone produced in the United States - especially in the state of Oregon.

“Oregon Sunstone” is now a very popular gemstone in Oregon where most people have

heard of it. Many people who visit Oregon go home with a piece of Oregon Sunstone jewelry and this spreads the word about sunstone to other areas.

Sunstone is not often seen in jewelry stores in most parts of the world. It is mainly used by innovative jewelry designers and those who enjoy surprising customers with interesting pieces. The small amount of sunstone entering the market as calibrated stones has limited its use in mass production jewelry.

As a feldspar mineral, sunstone has a hardness of 6 on the Mohs Hardness Scale and perfect cleavage in two directions. This makes it best suited for earrings, brooches, small pendants and other jewelry items that will not be exposed to rough wear. When used in rings it is best set in bezel, flush or recessed settings where the stone will be protected from impact.

Quality sunstone is a wonderful gem but getting people to notice its aventurescence is a marketing challenge. Jewelers who display it in ways that feature its aventurescence or demonstrate it with enthusiasm are often rewarded with sales. Its all about educating the buyer about the gem's greatest asset.

Mystical Properties:

Sunstone has a very positive effect on one's psyche, it promotes good humor, cheerfulness and an even temper. It may provide the necessary stamina and energy to undertake projects and tasks that one may find daunting.

It offers self-confidence and helps its wearer to discover her own nature and live accordingly. It assists its wearer in maintaining a positive attitude towards her own life and to use inherent strengths while still allowing the sunny side of the personality raise to the forefront.

Keep Sunstone with you at all times if you have difficulty saying "no" to people, and you continually make sacrifices for others. Sunstone will detach your feelings of being discriminated against, disadvantaged or abandoned; it will remove inhibitions and hang up, reversing feelings of failure. It will increase feelings of self-worth, and confidence encouraging optimism and enthusiasm. It will switch all feelings to a positive take on any event. Even the most incorrigible pessimist will respond to Sunstone.

Healing Properties:

Sunstone enables and enhances it's wearer with self-healing powers. It stimulates the vegetative, autonomic nervous system and enhances the harmonious functioning of all the body's organs. It is quite helpful in cases of exhaustion due to lack of sleep.

It will treat chronic sore throats and relieves the pain of stomach ulcers. It is quite successful on Seasonal Affective Disorder (or SAD), it is also known to relieve cartilage problems, rheumatism and general aches and pains.

Sunstone will lift depression and free it's wearer from feelings of discrimination and failure as well as images of an 'evil world'. Sunstone easily increases a sense of self-esteem as well as

self-worth.

Sunstone is particularly beneficial when used in the sun, sunshine, or sunlight.

Magical Properties:

Energy: Projective

Element: Fire

Powers: Protection, energy, health, sexual energy

Sunstone and Moonstone together are often used in Solstice rituals, either on the altar of by having the priest wear sunstone and the priestess wearing moonstone, thus representing the balance of power between the physical, psychic and spiritual attributes.

Sunstone also helps to find and keep a beneficial sexual relationship, it is a protective and powerful stone. This gemstone adds energy to other stones as well as to rituals and spell workings. Symbolically Sunstone is linked to Moonstone.

Chakra Classification:

Sunstone is most effective on the 2nd, or Sacral/Navel Chakra, but will clear all chakras, and to assist one in self nurturing.

Placed on the 3rd, or Solar Plexus Chakra, Sunstone will lift out heavy and/or repressed emotions and transmutes them very effectively.

Sunstone is quite useful in removing 'hooks' from other people or 'chording' whether located in the chakras or the aura. These hooks can be at the emotional or mental level, and may come from possessive parents, children, friends or lovers. They have the effect of draining your energy, often when you least expect to feel drained. Sunstone lovingly returns the contact to the other persona and is quite beneficial for cutting those ties.

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