Not so Common of the Feldspars !

The first Feldspar, seen below, is a very popular healy-feelie stone found in California with a close cousin from China. The stones from both locations have the same name. Now, contrary to very popular beliefs, it is not a black stone with Andalusite crystals embedded in it. That is how some web sellers offering this particular stone describes it. Wrong, wrong, wrong.

So the question becomes -- what kind of Feldspar is it? Like Unakite, this stone is a composite that features lightly-colored 'calligraphic-like' feldspar crystals called 'phenocrysts' enclosed by a dark matrix of Basalt called the groundmass. Since the helter-skelter arrangement of the crystals rightfully reminds one of Chinese calligraphy, this rock was named "Chinese Writing Stone" in 1980. How these Feldspar crystals got mis-identified as Andalusite in unknown.
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The second Feldspar type stone was originally said to contain four types of Feldspars. In actuallity, only one of its constituent minerals – anorthoclase – is a Feldspar. The other three minerals are two amphiboles (riebeckite and arfvedsonite) and a pyroxene (aegirine).
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Feldspar is a rather expansive group of stones having many members that could one day qualify for ornamental uses as an increasingly eco-minded public begins to discover and delight in the dirt-cheap (pun intended) glories of the earth’s crust. But our Nebula Stone, shown above, is more of a hanger-on than a full fledged membern of the Feldspar grouping, unlike the fully accepted Feldspar gemstones called Sunstone, Moonstone and Andesine or more lapidary type stones like Labradorite, Amazonite and Larvikite, to name a few.
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Thanks to Colored Stone Magazine for info and pictures.

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Oregon's "Sunstone" !

The 1987 Legislature designated the Oregon Sunstone as the official state gemstone. Uncommon in its composition, clarity, and colors, it is a large, brightly colored transparent gem in the Feldspar family. The Oregon Sunstone attracts collectors and miners and has been identified as a boon to tourism and economic development in southeastern Oregon counties.

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A few years earlier, in 1965, the Thunder-egg (geode) was named state rock by the Legislature after rockhounds throughout Oregon voted it as their first choice. Thundereggs range in diameter from less than one inch to over four feet. Nondescript on the outside, they reveal exquisite designs in a wide range of colors when cut and polished. They are found chiefly in Crook, Jefferson, Malheur, Wasco and Wheeler counties.

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Oregon Sunstone is a Feldspar crystal formed as phenocrysts in molten lava and then discharged onto the surface of the earth by a volcano. As the lava weathers away or is broken up the crystals are released. While Feldspars are found all over the world, they are rarely gem grade. Central Oregon is one of the few places in the world where this type of Feldspar is found in gem grade and large enough to cut stones for jewelry. Sunstone is a plagioclase Feldspar exhibiting in certain directions a brilliant spangled appearance, which has led to its use as a gemstone. Oregon is the only place in the world where gem grade Sunstones are found containing copper. Varying amounts of copper cause the stones to range in color from water clear to yellow, as well as many shades of green, red and pink. Some stones contain from two to four of these colors. Some rare stones will even change colors in different light as Alexandrite does, and some are different colors when viewed from different directions (dichroic and trichroic)..

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In south central Oregon, northeast of Plush, the BLM has set aside 4 square miles for rock collectors to hunt for Sunstones. No claims can be filled within the BLM sunstone area, and there is no charge to prospect. Outside the BLM area, several major mines exist ihat are open to the public for digging and collecting. High Desert Gems & Minerals currently owns over 40 sunstone mining claims in the Plush and White Horse Ranch area of Oregon. One, the Spectrum Mine is a 20 acre patented mining claim located 27 miles northeast of Plush, Oregon. Another major mine in the area, the Dust Devil Mining Company, is Oregon’s premier Sunstone Fee-Digging venue where visitors can prospect virgin ground that has been opened with our heavy equipment – They are never limited to digging tailings or material that has already been high-graded. Visitors will take most of what they find FREE OF CHARGE, while certain very high-grade or collector stones will be charged at 25% of wholesale. The Dust Devil Mine is a bit hard to get to, but they have files for downloading to GPS units on their web-site. About 100 miles to the southeast is another Sunstone location, with the major mining carried out is at the Ponderosa Mine in Harney County. The Ponderosa is a relatively recent find, having been discovered in 1980.

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In general, Feldspar, also called Labradorite, is a little known and underrated gemstone, yet some of the available colors and varieties of material are truly beautiful. At a hardness of 6, it is generally too soft for daily use in rings, it would be acceptable for occasional wear for special occasions and other types of jewelry. Feldspar is an easy material to cut, both in cabs and for faceting. The two perfect cleavages are not troublesome, and in fact, the table for faceted stones does not always have to be oriented away from the cleavage planes. The material is not heat sensitive and polishing usually goes fairly quickly with Cerium Oxide.

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Thanks to the owners of the Dust Devil MIne for their pictures and sample sunstone specimuns.

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Florida's "Moonstone" !

Moonstone is characterised by an enchanting play of light. Indeed it owes its name to that mysterious shimmer which always looks different when the stone is moved and is known in the trade as 'adularescence'. This enchanting gemstone belongs to the large mineral group of the feldspars, of which almost two thirds of all the rocks on Earth consist. Moonstone is actually the feldspar variety known as 'adularia', a potassium aluminosilicate of gemstone quality. In earlier times, people believed they could recognise in it the crescent and waning phases of the moon. Moonstones from Sri Lanka, the classical country of origin of the moonstone, shimmer in pale blue on an almost transparent background. Specimens from India feature a nebulous interplay of light and shadow on a background of beige-brown, green, orange or brown. These discreet colours, in connection with the fine shimmer, make the moonstone an ideal gemstone for jewellery with a sensual, feminine aura.

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United States astronauts Neil Armstrong and "Buzz" Aldrin landed on the moon July 20, 1969, preparing for man's first personal inspection of the lunar surface. Since the Apollo 11 and all other manned spaceflights had blasted off from the Kennedy Space Center in Brevard County, it came as no coincidence that the State Legislature sought to memorialize America's unprecedented international, scientific and technological triumph. Therefore, ten months later, May 20, 1970, Florida lawmakers passed and sent to the Governor a bill adopting the 'Moonstone' as the official State Gemstone of Florida.

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Ironically, Moonstone is not found naturally in Florida... nor was it found on the moon. It is a symbolic named official gemstone.

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