Anorthite Gemstone: Properties, Meanings, Value & More

Anorthite (uh-nore-thyte) is a widely distributed rock-forming mineral but a rare and obscure gemstone! It usually occurs in grayish-white colors with hints of red or pale orange and has a grainy texture similar to moon-rock. 

Does that mean anorthite has lunar roots? Kind of! Anorthite occurs in mafic (iron- and magnesium-rich) igneous rocks. The mineral is rare on the Earth but abundant on the moon. It’s even been found in meteorites! Far out, right?

Is anorthite a plagioclase? Yes! In fact, anorthite plagioclase may be the rarest of the plagioclase feldspar series. 

Also referred to as the anorthite and albite system, this group of feldspar minerals all share similar formulas but vary in sodium and calcium content. Anorthite is the calcium-rich end member of the series.

So what is anorthite used for and where can you find it? Keep reading to learn all about anorthite’s uses, meanings, composition, value, and more in our Anorthite Gemstone Guide! 

About Anorthite Stone

The mineral’s name derives from the Greek words an plus orthos, meaning “oblique” or "not straight" because the crystal’s faces meet at an oblique (slanted) angle. It’s sometimes referred to as “black moonstone.”  

Anorthite (not to be confused with anorthosite) is a rare and hard-to-find semi-precious gemstone. Mostly ornamental, it’s a lesser-known crystal to those outside the realm of astute collectors and geologists.  

What is the difference between anorthite and anorthosite anyway? Anorthite is a compositional variety of plagioclase that’s super rare on earth but widely abundant in moon rocks. On the other hand, anorthosite is an intrusive igneous rock characterized by a predominance of plagioclase feldspar and phaneritic texture (having visible crystals inside). Anorthite sometimes occurs within anorthosite.

While it’s not an official zodiac stone, it’s believed that anorthite suits the Leo and Scorpio signs in astrology. 

Fun fact: manufacturers of glass and ceramics sometimes use anorthite during production.

Curious to know how you can identify anorthite? Let’s check out its mineral traits!

Anorthite Composition & Characteristics

First, what is anorthite made up of? Anorthite has a chemical formula of CaAl2SiO8. It’s a calcium-aluminum silicate containing approximately 43% silica, 37% aluminum oxide, and 20% calcium. Possible impurities are iron, strontium, barium, titanium, and potassium. 

Anorthite’s color usually varies between white and gray (sometimes reddish-orange) with a white to colorless streak. Typically, in a thin section, anorthite is colorless and appears sprinkled with confetti-like plagioclase feldspar grains. 

Falling between 6 and 6 ½ on the Mohs hardness scale, anorthite is a semi-fragile mineral with a luster like frosted glass. It has an uneven shell-like fracture that’s translucent to opaque and looks almost muddy. 

In nature, anorthite occurs in granular or solid mass forms, as well as prismatic crystals. During weathering, anorthite crystals lose their natural luster, developing a white coating and rougher surface (containing clay mixture and hydromica).

Here’s an overview of all the anorthite properties:

• Mineral family: Feldspar

• Composition: Calcium aluminum silicate

• Mohs hardness: 6.0 to 6.5

• Color: White, grayish, reddish; Colorless in thin section

• Crystal structure: Triclinic

• Crystal habit: Granular

• Luster: Vitreous

• Transparency: Translucent to opaque; Rarely transparent

• Refractive index: 1.57 – 1.59; Biaxial (–)

• Density: 2.74 to 2.76

• Cleavage: Perfect on {001}, less so on {010}, imperfect on {110}

• Fracture: Conchoidal to Uneven

• Streak: Colorless

• Luminescence: Fluorescence (Pale yellow in LW-UV; White in SW-UV)

• Pleochroism: Present; Iridescent to colorless. 

Scientists have synthesized anorthite for mineralogical research, but there’s no known jewelry use for synthetic anorthite.

Onto history!

Image credit: Lunar and Planetary Institute, Lunar Sample Atlas, Sample 62275; James Stuby based on NASA image

Anorthite History

Anorthite was first discovered on Mount Vesuvius (Italy) by Gustav Rose, a German mineralogist, in 1823. He discovered fifteen new minerals in his lifetime — anorthite being the most significant.

Earlier, we mentioned that anorthite could be found on the moon. Well, it actually makes up much of its lunar highlands! 

In 1971, Apollo 15 astronauts David Scott and Jim Irwin brought back a hand sample of moon rock with a peculiar “little white corner.” The rock, now known as Genesis Rock, was made of anorthosite, and that little white corner turned out to be… you guessed it, anorthite! 

Even though anorthite is a fairly abundant mineral, gem-quality specimens are hard to come by. One locality on Great Sitkin Island, Alaska, has yielded pale yellow gems as big as 8 cts — possibly the largest known to man!

Time to shift gears and dive into anorthite’s metaphysical healing abilities.  

Pictured: Amazonite

Anorthite Healing Properties

Like most crystals, anorthite uses its energy and vibrations to support your physical, mental, and spiritual wellness — making it a powerful healing stone! 

The anorthite gemstone meaning is synonymous with many members of the plagioclase feldspar group — like albite, amazonite, labradorite, moonstone, or sunstone, to name a few. 

Most agree that anorthite, in particular, is a stone of restoration for the mind, body, and soul. Its ties to the moon are also associated with the divine feminine and goddess energy. 

Let’s explore how you can harness anorthite’s metaphysical properties to serve you! 

Physical Healing

Physically, what is anorthite used for? Its restorative energies may help ease pain, lower blood pressure, and promote relaxation. It can also help with restoring mental clarity and logical thinking. 

For women, anorthite can be especially supportive. Its feminine energy is said to help relieve menstrual pains such as cramps and body aches, as well as soothe the flow of blood. 

Emotional Healing

Emotionally, anorthite is believed to boost your confidence, determination, and self-worth. It supports those healing from emotional traumas by allowing you to regain your energy from the surface deep down to your subconscious. 

Anorthite’s goddess energy also inspires women to embrace their femininity and power to create life. Anorthite passes its feminine vibrations to you — making you feel like a divine, feminine goddess. How’s that for a confidence boost?

Chakra Healing

Some gems are especially attuned to one of seven chakras (energy points) along your body. These chakra stones help activate or balance your chakral body, keeping you in a constant state of flow. 

Anorthite’s associations to restoration and awakened freedom are believed to resonate with your third eye chakra. Meditating with anorthite can activate your third eye to encourage truth, flexibility, clarity, and deeper consciousness. 

Now that we know how anorthite can upgrade your overall wellness, let’s learn how the gems are graded! 

Anorthite Gemstone Properties

As abundant as the material is, pure anorthite is extremely rare and hard to come by. That’s because it weathers quite easily. If you do happen to get your hands on some, gems are generally graded by the industry-standard categories of color, cut, clarity, and weight (in carats for gems and size dimensions for rough, uncut specimens). 

Color

Anorthite is typically sold uncut and appears in dusty black, white, and sometimes reddish hues due to iron impurities. 

When cut to a gem, it can appear milky white, yellow, red, pink, or colorless. They are almost never transparent. 

Because of the gem’s rarity, color doesn’t seem to impact price all that much. 

Cut

Pure anorthite is mostly a collector’s crystal, usually sold rough. It has a rigid, granular, and sometimes bubbly texture.

When used as a gem, anorthite is rarely cut en cabochon. More often, anorthite is faceted, but gems are typically quite small as a result of their obscurity. 

As a semi-fragile stone, protective settings in jewelry are recommended.

Clarity

Anorthite crystals are rarely transparent, making gem-quality specimens (with good transparency) even rarer. 

Some gems have high clarity, while others are more moderate. When cut, they are usually moderately included, meaning they have some visible inclusions. 

Carat Weight & Size

Fancy cuts of anorthite tend to stay under around 4 cts. 

On the other hand, rough anorthite can be sold in specimens as large as 6 cm. The bigger the gem, the higher the price. 

Wondering how anorthite is formed? That’s next!

Image credit:  Anorthite — exposed in the Royal Ontario Museum, Toronto, Canada

Anorthite Formation & Sources

Anorthite is a rare compositional variety of plagioclase feldspar occurring in mafic igneous rocks. It also occurs in granulite facies, metamorphic rocks, metamorphosed carbonate rocks, and corundum deposits.

How does it get to the moon, though? It’s all thanks to plagioclase flotation in the lunar magma ocean (or so the hypothesis goes). 

In other words, scientists theorize that anorthite formed when feldspar crystallized and floated to the top of a magma ocean surrounding the moon after it formed.

Anorthite moon rocks are thought to be about 4 billion years old! 

So where is anorthite found today?

Mining Locations

Compared to the moon, anorthite is uncommon here on earth, but you can find it in a handful of localities. Aside from the moon, anorthite occurs in: 

• The lavas of Mount Vesuvius (Italy)

• Several localities across Japan

• A few localities in the USA 

Ready to splurge on your own anorthite? Let’s talk pricing!

Pictured: Labradorite

Anorthite Price & Value

As you’ve learned, anorthite is extremely rare. You’re more likely to find other feldspars occurring with anorthite. If perchance you find some anorthite for sale, here’s what to expect price-wise.

Rough anorthite, which is mostly ornamental, can vary in price. Most of the time, larger crystals fetch higher prices. However, anorthite also seems to fetch higher prices the older it is — sort of like wine!

For instance, some rough anorthite can cost between $3.05 to $15 per gram. However, some specimens (like one from 1870 Japan) cost as much as $70 per gram.

Despite its rarity, anorthite jewelry is generally inexpensive. Cabochons start at approximately $0.30 per carat. Faceted cuts, which are rarer, range between $42.72 to $62.20 per carat.

Now that you’re ready to snag your own anorthite, let’s go over gemstone care!

Anorthite Care and Maintenance

Taking care of your anorthite will ensure you get the most life out of your crystal! 

When cleaning your anorthite, run them under warm water. Use a gentle soap or detergent and a soft brush to remove grime. 

To prolong your anorthite’s lifespan, avoid letting your gem come into contact with:

• Ultrasonic cleaners

• Steam cleaners

• Abrasive chemicals

• Harder minerals

• Extreme changes in temperature

If you’re rockin’ some anorthite jewelry, remove it before partaking in any impact-prone activities (e.g. exercise, gardening, cleaning, etc.) To be safe, store your gems in a fabric-lined box or soft pouch away from other gems for extra security.

Shoot for the Moon with Anorthite!

Are you searching for a powerful crystal that holds the key to unleashing your divine femininity? Or simply looking for an obscure stone to add to your crystal collection? Anorthite’s lunar look and mystifying background will captivate you and anyone who feels its energy.

Bring a little intergalactic mystery into your home with anorthite!

Buy anorthite and other dazzling gemstones today!