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Pyrophyllite Gemstone: Properties, Meanings, Value & More

葉蠟石寶石：屬性、含義、價值等

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Pyrophyllite is a soft mineral used as a gemstone in decorative carvings. It’s also used industrially in various products from cosmetics to agriculture to metalworking.

The pyrophyllite mineral is quite similar to talc and the talc-dominant rock soapstone. What is the difference between talc and pyrophyllite?

Talc is a hydrated magnesium phyllosilicate while pyrophyllite is a hydrated aluminum phyllosilicate. While they’re both clay minerals, pyrophyllite is dioctahedral while talc is trioctahedral. You can’t distinguish them by eye — you’ll need chemical testing.

Pyrophyllite is more than just a talc simulant — this guide will teach you all of pyrophyllite’s history, properties, varieties, and meanings!

Image credit: John Sobolewski (JSS), CC-BY-SA-3.0

About Pyrophyllite Stone

Pyrophyllite is a semi-precious gemstone, though distinct crystals are virtually non-existent. The stone can be white, yellow, green, light blue, gray, or brown.

Other names for pyrophyllite include “ablikite” and “white mica.”

Industrially, some of pyrophyllite’s beneficial properties include:

• Low thermal and electrical conductivity

• Low expansion coefficient

• High refractive behavior

• Chemical inertness

• High resistance to corrosion by gasses and molten metals

• White color

• Smooth & soft

• Hydrophobic

We’ll discuss industrial uses later — first, let’s establish its mineral properties.

Pyrophyllite Specifications & Characteristics

As a phyllosilicate composed of aluminum silicate hydroxide, pyrophyllite’s chemical formula is Al2Si4O10(OH)2. The mineral is in the pyrophyllite-talc group alongside talc, willemseite, ferripyrophyllite, and minnesotaite.

Pyrophyllite has two polytypes: monoclinic pyrophyllite (2M) and triclinic pyrophyllite (1A).

The stone can occur as tabular (but curved and deformed) crystals or aggregates of radiating, needle-like crystals (often like interconnected fans), but distinct pyrophyllite crystals are extremely rare. The most common habits are foliated laminae (thin, stacked sheets) and compact masses. It can also be colloidal (gel-like).

Pyrophyllite has a flexible but inelastic tenacity, meaning under stress, it can bend without breaking but doesn’t return to its original shape.

How do you identify pyrophyllite? With a refractometer, you’ll see a vague shadow edge at about 1.6.

Pyrophyllite properties listed:

• Mohs hardness: 1-2

• Color: White, gray, pale blue, pale green, pale yellow, grayish-green, brown, brownish-yellow, brownish-green

• Crystal structure: Monoclinic or triclinic

• Luster: Pearly, dull, or greasy

• Transparency: Translucent to opaque

• Refractive index: 1.534-1.601

• Density: 2.65-2.90

• Cleavage: Perfect on {001}

• Fracture: Splintery or uneven/irregular

• Streak: White

• Luminescence: Fluorescence present in agalmatolite variety - cream-white in LW-UV

• Pleochroism: None

• Birefringence: 0.045-0.062

• Dispersion: Weak to none

Pictured above: Agalmatolite, variety of pyrophyllite | Image credit: 珍庵 at Japanese Wikipedia, CC-BY-SA-3.0

Types of Pyrophyllite

Many pyrophyllite varieties listed below are more so trade names than varieties, but they’re still important to know. The important types of pyrophyllite to know are:

Wonderstone

Wonderstone, or “koranna stone,” is a dark gray stone mined in South Africa. The rock is around 86 percent pyrophyllite, and blocks are sold for sculpture carvings.

This variety differs from the rhyolite or jasper varieties also called “wonderstone.”

Agalmatolite / Pagodite

Agalmatolite or pagodite is a grayish-green or grayish-yellow carving stone popularly used in Chinese carvings like those in pagodas (Hindu or Buddhist temples with tiered towers). In Japan, small pieces may be used as traditional writing tools.

This term can be used for pyrophyllite, talc, or pinite, along with rocks containing these and/or other clay minerals.

Cattle Egg Stone

Cattle egg stone is a dense pyrophyllite variety that’s black inside and yellow outside, often used for carvings. The colors come from iron oxide and diaspore mineral inclusions. The only referenced source is China.

Chrome-Pyrophyllite

Chrome-pyrophyllite is a green, chromium-bearing variety first found in Austria in 1961.

Onto pyrophyllite’s metaphysical properties!

Pictured above: Pyrophyllite figure pendant from Costa Rica | Image credit: Metropolitan Museum, Public Domain

Pyrophyllite Meaning & History

Metaphysically, pyrophyllite is nicknamed the “Creator’s Stone.” It symbolizes strength and resilience.

Pagoda carvings made with pyrophyllite are auspicious, representing wisdom and a path to higher perception.

History

German chemist Rudolf Hermann made the first official discovery of pyrophyllite in Russia in 1829. He named the mineral after the Greek terms pyro, for “fire,” and phyllos, for “leaf” alluding to how it swells up and exfoliates when heated.

The term “agalmatolite” was first recorded in 1801 and derives from the ancient Greek terms agalma, meaning “statue” or “figure,” and lithos, meaning “stone,” in reference to its use in Chinese carvings and figurines.

Historical Pyrophyllite Uses

Compact pyrophyllite has been used historically for carvings, slate pencils, and tailors’ chalk.

A carved pyrophyllite figure pendant from Costa Rica (pictured above) currently held at the Met Museum is dated between 300 to 800 AD!

Slate pencils were common in the 1800s. Schoolchildren used them to write on slate (the chalkboard precursor) because paper was expensive.

Tailors’ chalk, or “French chalk,” was used for making temporary marks on fabric while sewing and removing grease from dry cleaning. White French chalk powder can also be used by welders to mark metals.

What is the pyrophyllite stone used for now?

Pictured above: Buddhist seal made from Pyrophyllite found at the Liao Shangjing site | Image credit: BabelStone, CC-BY-SA-3.0

Modern Pyrophyllite Uses

Today, we know pyrophyllite is most useful when it’s pure or has high alumina content with low iron content (below 1 percent).

Some of the top applications are:

1. Refractory: Produces fairly low-cost refractories when converted into mullite

2. Cosmetics: Prevents sweat absorption and face/body pyrophyllite powders stick better; Safer alternative to talc

3. Fiberglass: Used for preparing batches of fiberglass, helps remove sand

4. Ceramics: Improves translucence, resistance to cracking, and firing times; Pyrophyllite ceramics include tiles, whiteware, plumbing fixtures, and electrical components like insulators

5. Paper Filler: Inexpensive and improves quality, softness, hydrophobicity, reflectance, and chemical inertness

6. Plastic Filler: High specific heat and electrical resistance used in computer cases and garden chairs; Mechanical strength used in car dashboards and bumpers

7. Paint Filler: Powder used as suspending agent that extends pigment, helps film dry, increases volume, and promotes dispersion; Affordable alternative to China clay

8. Insecticide Filler: Inexpensive, pH-neutral, doesn’t absorb moisture from air, easily sticks to plants

9. Soil Conditioner: Increases soil’s ability to hold nutrients, minimizes leaching, retains heavy metals

10. Dusting Agent: Improves quality, lubrication, and smoothing of rubber tires; Prevents adhesion and improves weather-resistance in roofing materials

Many industrial pyrophyllite compounds are called Torai “roseki” clays or PYRAX®.

Image credit: John Krygier, Public Domain

Pyrophyllite Healing Properties

As a commonly white healing stone, pyrophyllite joins other white gems in offering cleansing and spiritual ascension. Pyrophyllite is a chakra stone for the solar plexus and sacral chakras.

Physical Healing

Historically, natural clays like pyrophyllite have been used for healing skin infections, and some clays actually have antibacterial mechanisms.

Emotional Healing

Crystal healers recommend pyrophyllite for boosting concentration, self-confidence, and resilient positivity.

Pictured above: Pyrophyllite inclusions in quartz cabochon

Pyrophyllite Gemstone Properties

Pyrophyllite gems are valued on color, cut, and carat weight.

Color

Most pyrophyllites are light green to brownish-green, and massive specimens often have silver to yellow running throughout.

While bright, pure white pyrophyllites are usually preferred industrially, colors like greens and blues may be more desirable for gems.

Cut

Given pyrophyllite’s extremely low Mohs hardness and lack of distinct crystals, faceted gems are essentially non-existent. Massive material can become cabochons or carvings.

Most varieties, like agalmatolite, cattle egg stone, and wonderstone, are carved.

Clear quartz containing pyrophyllite inclusions is often sold as cabochons or faceted gems.

Carat Weight & Size

You can find pyrophyllite carvings and cabochons in practically any size. Crystal aggregates can be fairly large.

Image credit: Antonio Nazario, Public Domain

Pyrophyllite Formation & Sources

Pyrophyllite forms when aluminum-rich rocks undergo low-grade metamorphism or aluminum-rich minerals like feldspar are hydrothermally altered.

What types of rocks have pyrophyllite? Rocks containing pyrophyllite include schistose and phyllite rocks. Pyrophyllite also occurs in hydrothermal veins.

Minerals commonly found with pyrophyllite include andalusite, topaz, kyanite, quartz, and mica.

Mining Locations

Where is pyrophyllite mined? Pyrophyllite is mined all over the world, but significant locales for ornamental material include:

• Belgium

• Brazil

• Canada

• Italy

• Japan

• Korea

• Mexico

• Russia

• South Africa

• Sweden

• Switzerland

• USA (Arizona, California, Georgia, North Carolina, Pennsylvania)

Image credit: Rock Currier, CC-BY-SA-3.0

Pyrophyllite Price & Value

How much is pyrophyllite worth? Attractive pyrophyllite crystal specimens usually range in price from about $5 to $20 for smaller specimens and $50 to $100 for larger ones.

Wonderstones are often sold in huge blocks (like 12 lbs to 73 lbs), ranging from about $90 to upwards of $850 each.

Pyrophyllite carvings and sculptures can go for $75 to $2,900.

Cabochons of pyrophyllite in clear quartz range from around $4 to $13 per carat or $55 to $160 each.

The industrial pyrophyllite market was valued at $151.7 million (USD) in 2019, and it’s estimated to be worth over $180 million by 2032.

Pyrophyllite Care and Maintenance

Is pyrophyllite toxic? Polished cabochons and carvings should be perfectly safe to handle, but pyrophyllite dust or particles (often produced when cutting rough material) can cause low category pneumoconiosis if you inhale a lot of it frequently.

Onto gemstone care, you can clean pyrophyllite with warm water and mild soap. However, most materials will scratch it, so be extremely cautious. If you need to wipe off dust, only use a lint-free microfiber cloth or simply blow the dust away.

Store separately from other minerals.

Ready to Pick Your Pyrophyllite?

What pyrophyllite may lack in hardness, it makes up for in its beneficial properties and wide potential for beautiful carvings or decor. Add some earthy wonder to your space with pyrophyllite!

Buy pyrophyllite and other unique gemstones today!