The feldspars are a group of minerals that make up more than half of the Earth's crust (about 60% according to the GIA), and are classified by their composition made mostly of aluminum and silicates. While most feldspar may just look like typical rocks, some varieties are known for their ethereal shimmering appearance. There are many feldspar gemstones used in jewelry, but the biggest three are moonstone, labradorite, and sunstone.
Moonstone is a potassium feldspar that comes in several colors including colorless, white, peach, gray, brown, and green. This dreamy stone has a special property called adularescence, named after the city Mount Adular in Switzerland which was one of the first sources of fine-quality moonstone. This shimmery metallic-like sheen occurs when light reflects from within the layers of the stone and can appear as silvery white, blue, or gray. Moonstone is made up of many thin layers of alternating orthoclase and albite, and when light shines between these layers, the light is scattered creating the adularescence effect. Most moonstone is faceted into a rounded polished shape without facets, called a cabochon, which best highlights the ethereal glow of moonstone.
Moonstone has been used in jewelry for centuries, and the ancient Greeks and Romans believed it was made of literal solidified moon rays. Moonstone popularity has ebbed and flowed throughout time, but was a very popular choice in Art Nouveau jewelry. It is also a popular choice for modern jewelry because it is one of the three June birthstones alongside pearl and alexandrite.
Rainbow moonstone, what people typically think of when they hear the word "moonstone" is actually not a moonstone at all, but rather a type of labradorite. In fact, its sometimes even referred to in the industry as "white labradorite." While moonstone and rainbow moonstone are closely related, rainbow moonstone belongs to the plagioclase family of feldspars while regular moonstone is an orthoclase feldspar. It typically has a cloudy or milky white field that can be semi-translucent or opaque and can even include inclusions of black tourmaline. The adularescence in rainbow moonstone is predominantly blue, but can multi-colored and also include shades of orange, yellow, etc. hence the name "rainbow moonstone."
Labradorite is a plagioclase feldspar known for its beautiful play of color that includes flashes of blue, purple, orange, green, red, silver, yellow, etc. against a gray or black field. This colorful phenomenon combined with the glittery metallic inclusions (called schiller) in labradorite has earned its own name, called "labradorescence." Stones with the highest labradorescence are sometimes referred to as "spectrolite" for their breath-taking spectrum of color.
Labradorite gets its name from Labrador, Canada, where the stone was first discovered. The Inuits of Canada have legends describing the Northern Lights being trapped within the stone and used it to make ailments. Much of today's labradorite is supplied from Madagascar, Mexico, and Finland and has uses not only in jewelry, but for glass-making, construction, granite countertops, and more.
Sunstone varieties can be plagioclase (labradorite) or oligoclase feldspars depending on the type and source. Like the other feldspar stones, sunstone also sometimes displays a metallic-like luster, but it is not caused by the bouncing and scattering of light the same way as moonstone. Instead, this effect is caused by metallic inclusions within the stone - typically hematite or goethite. Sunstone from Oregon is unique in that the reddish-golden metallic inclusions within these stones are actually small pieces of copper rather than hematite. This glittery effect is referred to as schiller or aventurescence. Not all sunstones have schiller, however. Sunstones can range from containing many inclusions to being a translucent stone. Sunstone comes in colors ranging from yellow, orange, red, red-brown, colorless, and even green. Green and deep red are the most desirable sunstone colors, and some sunstones will even combine two or more colors in one stone. Oregon sunstones specifically have become popular among collectors for their natural beauty and ethical sourcing in the United States.
Rainbow Lattice Sunstone
Rainbow lattice sunstone is a newly-discovered variety of orthoclase feldspar that exhibits both the adularescence of moonstone as well as the adventurescence of sunstone in addition to iridescent lattice inclusions made up of extremely thin strips of magnetite. This incredibly rare single-source stone comes from Australia and is highly-sought after by gem and crystal collectors. Read more about rainbow lattice sunstone here.
Feldspar Jewelry Care and Cleaning
All the feldspar varieties we offer are softer stones that require special care in jewelry. Ranking between 6.5-7 on the Moh's scale of hardness with defined cleavage, feldspar stones can get scratched or fractured if not treated with care. We recommend setting feldspar stones in protective settings and following our Care Guidelines to help keep your center stone in good shape. If you are hard on your jewelry or wear your ring all the time, a feldspar stone may not be the best option for your lifestyle. One great thing about many feldspar stones - since feldspar is so abundant on Earth, it is often an affordable stone to replace if damage does occur.
Most feldspars are stable against light, but can be fractured by high heat or sudden changes in temperature. For this reason, they're best cleaned with warm water, mild soap, and a soft brush or cloth. We advise against using steam cleaners or ultrasonic cleaners on feldspar jewelry.
Find or Design a Moonstone, Sunstone, or Labradorite Ring
At Staghead Designs, we are passionate about handcrafting unique wedding rings with alternative stones and materials, making feldspar a great fit for our custom designs! We work with all of the feldspars discussed above and have many designs on our site that use these magical stones (even men's bands). Whether you want a feldspar center stone, or just to add an ethereal touch with some accent stones, we are happy to work with you to create the perfect design that is meaningful to your relationship. Browse through our collections of customizable rings here, or reach out to start designing your own perfect moonstone, labradorite, or sunstone ring today!