Feldspar – The unknown Beauty

Last month I wrote about the beautiful gemstones in the quartz family like amethyst and citrine.  Because quartz is so common, most everyone has heard of it and its gemstones.  However, quartz is only the second most common mineral on earth.  Winning the gold medal for composing over 60% of the earth’s crust is feldspar.  While most feldspar that is mined or excavated is used in glass making and the manufacture of ceramics, rock hounds and gemologists know that certain feldspars make beautiful gems and mineral specimens.

custom moonstone rings
Men’s Moonstone Ring

The best known of the feldspar group of gems is moonstone. As you might have guessed, moonstone does not get its name because they were found on the moon, although rocks containing feldspars were brought back from the moon by the Apollo space missions.  Moonstones get their name for the sheen it gives off which resembles moonlight.  This play of light and color is called adularesence.  Opal is another gemstone that displays this effect.  It is caused by structural irregularities in the crystal formation.

moonstone jewelry
White Moonstone Pendant

Most moonstones are white, but the most desirable color is those with a bluish color sheen.  Other colors that moonstones come in are green, yellow, orange, brown, pink, purple, and grey, but these colors are less common and less desirable.  Moonstones are primarily found in India, Sri Lanka, Myanmar, and Australia.

sunstone jewelry

An interesting gem in the feldspar family is sunstone.  It is interesting because sunstone literally glitters!  The effect is caused by inclusions of hematite or pyrite in the stone.  Sunstones are usually orange or red, and are found in India, Norway, Russia, Madagascar, and the state of Oregon, where it is the state gemstone.

custom jewelry

Another important gemstone that is a feldspar is labradorite.  Labradorite displays an iridescent play of colors which move as the stone moves.  Labradorite usually has a dark base color with blues, greens, yellows, and reds as plays of color.  This play of colors is caused by internal fractures in the mineral that reflects light, dispersing it into different colors.

custom jewelry

Andesine may or may not be a separate gemstone in the feldspar family.  When first “discovered” in 2003, the story goes that it was mined in the Congo region of Africa.  The problem with this story is that it could not be authenticated.  Most andesine in the market are labradorites that has been diffused with copper (using chemicals and heat to change the surface color.  Andesine is usually red, reddish-pink, or orangy pink.  All the andesine being sold comes from Inner Mongolia and is treated by the Chinese before it is sold.  Some less than reputable dealers try to sell andesine as Oregon Sunstone in order to get a higher price, but the difference between the two is almost immediately apparent by the glitter effect of the sunstone.

gemstone jewelry

Orthoclase is the last of the faceted feldspars and technically, what the industry calls orthoclase – isn’t!  Orthoclase the gemstone is in reality a rare transparent form of the mineral sanidine.  This discovery has only recently occurred, but because the industry already established the name orthoclase for this gemstone, it has remained known as such.  Yellow is the main color of this gemstone, but greenish stones have started to appear in the marketplace.  The vast majority of orthoclase comes from Madagascar, but small quantities have been found in the usual gemstone locations of Brazil, Myanmar, and Tanzania.


The final gemstone on the list is amazonite.  Now before you jump the gun and assume that this gem is found in the Amazon, you would be wrong.  Amazonite gets its name from lush greenery of the Amazon jungle which its color resembles.  Personally, I think that this is the most beautiful of all the feldspar gemstones.  Because it is translucent to opaque, amazonite is never faceted but polished into beads, cabochons, carvings, or left in its natural state to be displayed as a mineral specimen.  Its natural color is greenish with white streaks.  Amazonite is found worldwide, but large deposits exist in Russia, Myanmar (Burma), India, Ethiopia, Madagascar, Brazil, and the United States (Colorado and Virginia).

As you can see, even the most common minerals on earth can be beautiful gemstones.  If you are interested in these or any other gemstones, or anything for your custom jewelry needs, contact us at Images Jewelers.

Author: Shawn

Indiana University Alumni GIA Graduate Gemologist Student

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