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Periclase Gemstone: Properties, Meanings, Value & More

ペリクレースの宝石：特性、意味、価値など

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Periclase is a natural magnesium oxide mineral best known for being a standard in mineralogical and physics research, along with having other commercial uses. Periclase has even been found in meteorites from the solar nebula!

Is periclase rare? The mineral is fairly common, but facetable material is extremely rare, making faceted periclase gemstones small and hard to find.

That said, synthetic periclase has been created for both research and gemstone purposes. When sold as a gemstone, synthetic periclase is sometimes called “lavernite.”

Want to learn more? Stick around to find out all of periclase’s properties, prices, powers, history, and more!

Pictured above: Greenish nickel-bearing periclase with black srebrodolskite | Image credit: Thomas Witzke, CC-BY-SA-3.0

About Periclase Stone

Periclase is a rare natural semi-precious gemstone, though synthetic options are available. Other spellings for the stone’s name include:

• Periclasa

• Periclasia

• Periclasite

Based on their appearances and some overlapping gemological properties like refractive indices, optic character, and density, green periclase (especially synthetic specimens) can sometimes be confused with green grossular garnet.

However, one potentially distinguishing feature (besides chemical analysis) is grossular garnet’s fluorescence.

Its similar appearance to grossular garnet makes it an alternative option for January birthstones and 2nd wedding anniversaries.

What is Periclase Used For?

Both natural and synthetic periclase has a variety of industrial and research uses.

Due to the simplicity of periclase’s structure (similar to that of halite) and its high stability, it’s often used as a control standard in experimental mineral and physics studies.

Both natural and synthetic periclase are used industrially. For example, periclase is used to make bricks for refractory furnace linings. In fact, the most important refractory mineral for making metals is periclase, found in refractories for:

• Spinel-magnesia

• Chrome-magnesia

• Forsterite-magnesia

• Magnesia

• Dead-burned dolomite

Periclase can also be used as an electrically isolating metal gasket cover in diamond anvil cells, which are devices used to put tiny materials under extreme pressures. This may be in part because periclase remains stable up to at least 360 GPa (gigapascals) of pressure.

Pictured above: Sample of magnesium oxide powder | Image credit: Adam Rędzikowski, CC-BY-SA-4.0

Periclase Specifications & Characteristics

As a magnesium oxide mineral, the periclase formula is MgO. Iron, nickel, manganese, and zinc can substitute for magnesium in the formula. The mineral periclase is in the periclase group.

Besides periclase, what are the minerals in the periclase group? They are:

• Bunsenite (nickel oxide)

• Manganosite (manganese oxide)

• Wüstite (iron oxide)

Wüstite and periclase form a solid solution series, with wüstite as the iron endmember and periclase as the magnesium endmember. Intermediate members may be called ferropericlase (iron-bearing periclase) or magnesiowüstite (magnesium-bearing wüstite), and these two names are generally synonymous.

What is the crystal habit of periclase? Most often, periclase occurs as rounded or irregular grains, usually of anhedral to subhedral crystals in a rock matrix like marble.

It can also occur as octahedral, cuboctahedral, cubic, or dodecahedral crystals — octahedral being the most common among these. Crystals may be clustered. The mineral also occurs in massive habits.

Periclase properties listed:

• Mohs hardness: 5.5-6

• Color: Colorless, white, grayish-white, gray, yellow, brownish-yellow, green, black

• Crystal structure: Isometric/cubic

• Luster: Vitreous or sub-vitreous

• Transparency: Transparent to translucent

• Refractive index: 1.732-1.745

• Density: 3.55-3.68

• Cleavage: Perfect on {001}, imperfect on {111}; Sometimes parting on {011}

• Fracture: Uneven/irregular or conchoidal

• Streak: White

• Luminescence: Fluorescence sometimes present - pale yellow in LW-UV

• Pleochroism: None

• Birefringence: None

• Dispersion: Unknown

• Optical phenomena: Very rarely adularescence

Pictured above: Tactite rock containing periclase, calcite, ferroan spinel, and other magnesium-titanium borate minerals | Image credit: James St. John, CC-BY-SA-2.0

Periclase History

Periclase was first officially described by Italian physician and mineralogist Arcangelo Scacchi in 1841 based on specimens from Mount Somma in Campania, Italy, now the mineral’s type locality. The type material was found in the Monte Somma volcano inside altered limestone xenoliths near forsterite, magnesite, and hydromagnesite.

Scacchi named the stone “periclasia” from the Greek terms peri meaning “around” and klasis meaning “fracture” in reference to the mineral’s perfect cleavage.

Synthetic periclase gemstones were first sold in the jewelry market in 1969 under the name “Lavernite.”

However, periclase stones were also known in ancient times as “magnesia” or “Stones of Magnesia,” as magnesium oxide (periclase), hydrated magnesium carbonate (hydromagnesite), and iron oxide minerals (like magnetite) were found in the Magnesia region of ancient Anatolia.

In fact, these minerals’ magnetic properties eventually led to the words “magnetism” and “magnet.” The word “magnet” is Greek and it came into the Latin language around 100 AD, then into English around 500-600 AD when it appeared as lapidary instructions to explain what many previously thought was a supernatural or spiritual phenomenon.

Speaking of spiritual phenomena, what is periclase used for in spiritual healing?

Periclase Healing Properties

Mostly known as a green healing stone, periclase’s meaning reflects the relaxing and hopeful properties of other green gemstones. It’s also used as a heart chakra stone.

Physical Healing

Physically, periclase is said to treat problems related to:

• Digestion

• Headaches

• Respiratory health

• Blood circulation

Emotional Healing

Emotionally, crystal healers recommend periclase for:

• Dispelling anxiety and melancholy

• Grounding

• Promoting bravery and strength

Pictured above: Small white periclase specimen from Crestmore, California, USA, in UBC Geological Museum Mineral Collection | Image credit: Pacific Museum of Earth from Canada, CC-BY-SA-2.0

Periclase Gemstone Properties

Periclase gemstones value depends on its color, cut, clarity, transparency, and carat weight, along with if its natural or synthetic.

Color

Periclase can be found in colorless, white, gray, or black, along with brighter hues like yellow, green, or brownish-yellow. Green or black colors in natural material usually come from inclusions. Many colors arise from impurities, like:

• Iron – brown

• Chromium – green (often synthetic)

• Chromium and iron – green

• Manganese and zinc – grass-green

Brighter, more pure colors are more valuable.

Cut

Since natural facetable rough is extremely scarce, these periclase gems can carry significant value. Most faceted periclase stones are synthetic. Common cuts are rectangular or emerald shapes.

Periclase can also be cut as cabochons or sold rough (uncut).

Clarity & Transparency

Clarity describes the degree of visible inclusions in a gem, which can lower its transparency and value.

One exception is in a rare periclase cabochon from Myanmar (noted by the Gemological Institute of America, GIA, in 2003) which contained liquid inclusions that gave it adularescence, the internal glowing effect seen in gems like moonstone, and increased its value.

Though periclase is translucent to transparent, its transparency can be hard to see in the small size of available facetable natural rough.

Various inclusions have been found in synthetic periclase stones, including:

• Merwinite

• Monticellite-forsterite series, sometimes with strange skeletal radiating growth

• Perpendicular cracks

• Cement hardener (dicalcium or tricalcium silicate)

• Black “rubber” slag particles (phosphorus-bearing)

• Solid phases with flame-like structure

• Calcite and aragonite nano-crystals or particles (usually synthetic)

• Hematite

• Multi-phase fluid inclusions with unmixed liquids and gas phases

• Triangular- or rectangular-shaped fluid inclusions

• Spherical inclusions compatible with olivine phases of forsterite-monticellite series

• Plate-like negative crystals with square shapes

• Pinpoint clouds

• Small round bubbles

The inclusions present can depend on how the periclase was synthesized.

Carat Weight & Size

Most natural facetable periclase rough is quite small, making these gems almost always under 1 carat. Synthetic periclase gems can be much larger, with some gem-quality synthetic rough over 115 carats.

Synthetics

By now, you know there’s plenty of synthetic periclase out there. It’s created in a variety of ways, from refractory magnesia production (as a byproduct) to carbon arc-fusion techniques. Scientists are still working on more techniques, meaning synthetic periclase gems could be more widely available in the future.

The lack of large natural periclase gems can make identifying synthetic periclase difficult, as gemologists don’t have much natural material as a base for comparison.

Pictured above: Small, translucent, grayish-green periclase crystals festooned on matrix from ancient pumice mine | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Periclase Formation & Sources

Periclase minerals form due to contact metamorphism at high temperatures inside marbles. These marbles formed when dolomite limestones underwent metamorphism. It can also be found in other contact metamorphic rocks like magnesian-skarn and brucite-marble.

If periclase undergoes low-grade metamorphism, it turns into brucite. Periclase can also alter to brucite and other magnesium minerals from hydration, like humidity conditions.

Mining Locations

Natural grains that can be cut into gems are mainly found in California (USA) and Italy. Other significant locales include:

• Australia

• Canada

• Czechia

• Germany

• Ireland

• Russia

• Slovakia

• Spain

• Sweden

• USA (Arizona, Nevada, New Mexico, Texas)

Periclase Price & Value

Currently, there aren’t many faceted periclase gemstones on the market, so determining a general price isn’t feasible currently.

However, you can find plenty of rough periclase specimens for sale.

Rough periclase specimens range from around $30 to $70 each, unless it’s a giant specimen containing other minerals, which can be upwards of $500.

Pictured above: Periclase microcrystals under electron microscope | Image credit: Dertyren33, CC-BY-SA-4.0

Periclase Care and Maintenance

In terms of gemstone care, periclase hardness is relatively good, but its perfect cleavage means it can break easily with a sharp blow. Any periclase jewelry should have protective settings.

One major consideration is that faceted synthetic periclase gems often develop a thin layer of brucite on their surface due to contact with humidity. Therefore, keep periclase in a cool, dry place and only wipe it down with a soft, dry cloth.

Does Periclase Pique Your Interest?

Periclase may not be a household name like say, peridot, but it’s no less beautiful. Whether natural or synthetic, periclase gemstones are the perfect treat for any gem lover or collector.

Buy periclase and other gemstones today!