Idocrase (Vesuvianite) Gem: Properties, Meanings & Value

Idocrase is a popular collector’s gemstone but lesser-known in the jewelry sphere. It’s commonly called “vesuvianite” after its discovery near Mount Vesuvius in Italy.

What color is idocrase? Gemstones are usually shades of green to brown, but the stone comes in various colors.

Is idocrase rare? Gem-quality idocrase is rare, but the mineral is pretty common.

Stay tuned to learn all about idocrase uses, properties, prices, powers, and more!

What Is An Idocrase Gemstone?

Idocrase is a semi-precious gemstone often called “vesuvianite.” The name “vesuvianite” is usually preferred by geologists, while “idocrase” is common among gemologists.

Other monikers include:

• Dupracite

• Genevite

• Jefreinoffite / Jevreinovite

• Gahnite

• Pyramidal Garnet (misnomer)

• Volcanic Chrysotile (misnomer)

This crystal is an astrological talisman for Sagittarius and Capricorn. Though not a traditional birthstone, idocrase can substitute for jade as a March birthstone.

Wait, is jade an idocrase? No, but they’re commonly confused. Idocrase is actually a common simulant for jadeite, but idocrase usually has a higher refractive index.

Pictured above: Grossular garnet on idocrase | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Idocrase Specifications & Characteristics

On a basic level, idocrase is a calcium magnesium aluminum silicate. The idocrase formula is complex and varies somewhat by source. The formula approved by the International Mineralogical Association (IMA) is (Ca,Na)19(Al,Mg,Fe)13(SiO4)10(Si2O7)4(OH,F,O)10.

Potential impurities include:

• Antimony

• Beryllium

• Boron

• Fluorine

• Cerium

• Chromium

• Copper

• Iron

• Lithium

• Manganese

• Potassium

• Rare earth elements (uranium, thorium)

• Sodium

• Water

• Tin

• Titanium

• Zinc

Most common are iron, magnesium fluorine, water, and boron. The various impurities and other minerals intergrown with idocrase make its properties somewhat variable.

The mineral is in the vesuvianite group. It’s isostructural (similar chemical structures) with fluorvesuvianite, manganvesuvianite, and wiluite.

Many idocrase crystals are well-developed. They can be prismatic, pyramidal, or columnar. The prism planes are typically striated lengthwise, while the basal planes are smooth. Idocrase can also occur as granular or massive specimens, often intergrown with grossular garnet.

Idocrase properties listed:

• Mohs hardness: 6-7

• Color: Usually shades of yellow, green, or brown; Sometimes white, colorless, black, red, pink, purple, violet, blue, or blue-green; Crystals often color-zoned

• Crystal structure: Tetragonal

• Luster: Vitreous or resinous

• Transparency: Usually translucent to opaque; Rarely transparent

• Refractive index: 1.655-1.795

• Density: 3.32-3.50

• Cleavage: Poor/indistinct on {100} & {110}; Very poor on {001}

• Fracture: Conchoidal, subconchoidal, granular, or irregular/uneven

• Streak: White

• Luminescence: Fluorescence rarely present - yellow in SW-UV

• Pleochroism: Present but weak in colored stones - varying shades of crystal’s body color

• Birefringence: 0.003-0.006

• Dispersion: 0.019-0.025 (moderate)

• Optical phenomena: Rarely chatoyancy

Pictured above: Cyprine | Image credit: David Hospital, CC-BY-SA-4.0

Types of Idocrase

Idocrase has varieties based on impurities and locales.

Impurity-based varieties are:

• Xanthite: Contains 2.8 percent manganese oxide

• Manganese-bearing Vesuvianite: Contains some amount of manganese of unknown valance; Usually reddish to purple

• Beryllium-bearing Vesuvianite: Contains beryllium

• Frugardite: Contains magnesium; Discovered in Frugård, Finland

• Cerian Vesuvianite: Contains cerium

• Chrome-Vesuvianite: Contains chromium replacing some aluminum; Usually under 1 percent chromium oxide, rarely higher (like those containing up to 6.21 percent chromium oxide and up to 7.43 percent titanium dioxide found as diopside inclusions)

Onto the locale-based varieties:

Californite

Californite is a pale to medium green, massive mixture of idocrase and grossular garnet. It was discovered in California, USA, hence the name. The stone resembles jade, leading to the (erroneous) monikers: California jade, American jade, and vesuvianite jade.

Cyprine

Cyprine is a rare sky-blue variety of idocrase. The color comes from copper impurities and the stone is mostly found in Franklin, New Jersey.

Solairite

Solairite is a newer trade name for vesuvianites exclusive to Canada. These stones have traces of iron and titanium, creating a rich orange-brown color.

Wiluite

Wiluite is sometimes considered an idocrase variety distinguished for being optically positive and boran-rich. The dark green, black, or brownish stone was discovered in Wilui, Siberia.

However, many now consider wiluite its own distinct species.

Idocrase Meaning & History

Metaphysically, idocrase symbolizes spiritual ascension, strength, and emotional awareness. Some give idocrase as a wedding gift to represent harmony, partnership, and resilience.

History

The first name for this mineral wasn’t idocrase or vesuvianite, but rather hyacinthus dictus octodecahedricus, Latin for “hyacinth called octodecahedral.” Swiss physician Moritz Anton Kappeler proposed this name in 1723.

French mineralogist Jean-Baptiste Louis Romé de L'Isle proposed the name hyacinte du Vesuve, or “hyacinth from Vesuvius,” in 1772.

In 1795, German geologist Abraham Gottlob Werner chose the name “vesuvianite,” since high-quality crystals were found near Mount Vesuvius in Italy.

The next year in 1796, French mineralogist René Just Haüy suggested the name “idocrase.” This name derived from the Greek terms eidos, meaning “mixed” and krausis, meaning “form,” because the crystals were often mixed with other minerals, resulting in multiple forms.

The first description of californite came from American gemologist George Frederick Kunz in 1903. Kunz proposed the name “californite” after its discovery in California.

Wiluite was an even more recent find, discovered near the Wilui River (also spelled Vilyuy or Vilui River) region of Siberia, Russia in 1997. Some authors had previously proposed the name “viluite,” but “wiluite” was chosen in 1998.

Idocrase Healing Properties

As a primarily green healing stone, idocrase has the rejuvenating and harmonizing properties of green gemstones. Energy healers use it as a heart chakra stone.

What are the benefits of idocrase stones physically?

Physical Healing

Crystal healers recommend idocrase crystals for treating issues related to:

• Skin disorders

• Bone & muscle strength

• Digestion

• Nutrient absorption

• High heart rate

• Blood circulation

Emotional Healing

Emotionally, idocrase is said to relieve feelings of negativity, anxiety, and restriction. Crystal healers recommend the crystal for boosting creativity, balancing emotions, and promoting a strong sense of self.

Idocrase Gemstone Properties

Idocrase gemstone value depends on its color, cut, clarity, transparency, and carat weight.

Color

Most idocrase minerals are some shade of yellow, green, or brown, often a mixture of these. The best green shades like emerald-green, blue-green, or chartreuse are often most valuable.

That said, pale shades of lilac or blue can also be valuable, and the most expensive are usually deep shades of orange or red to purple idocrase.

Many stones are bi- or multi-colored, sometimes with streaks or spots of white, blue, reddish-brown, or yellow.

Cut

Since transparent, gem-quality idocrase is rare, it’s often faceted and quite valuable. Common cuts include checkerboard, emerald, round, oval, pear, cushion, and marquise shapes.

Many attractive massive specimens like californite are cut into cabochons or carvings. These can also be valuable, but not as valuable as faceted options.

Clarity & Transparency

Clarity, the degree of visible inclusions, can affect a stone’s transparency and value. Most idocrase gems are opaque, so stones with greater transparency are rarer, usually more lustrous, and more valuable.

Many minerals can be found as inclusions in idocrase, along with roiled growth structure, fingerprints, and veil-type inclusions.

Carat Weight & Size

While idocrase crystals can be fairly long, these aren’t usually transparent. Brown faceted gems are usually up to 10 carats max, while green ones are generally 15 carats max. Most faceted idocrase gems are 5-10 cts.

Cabochons can be much larger, with some over 100 carats available.

Idocrase Formation & Sources

Idocrase usually forms when carbonate rocks undergo contact or hydrothermal metamorphism. It’s usually found in limestones but also occurs in serpentine, gneiss, dolomite, marble, skarn, or granulite.

Mining Locations

Where is idocrase found? Gem-quality deposits are in Italy, Canada, Pakistan, Kenya, and New York (USA).

Other high-quality crystals are found in:

• Arkansas, USA

• Finland

• Japan

• Korea

• Mexico

• Switzerland

• Tanzania

• USA (Arkansas, Maine, Vermont, New Hampshire)

The localities of idocrase varieties are:

• Californite: California, USA; Africa; Pakistan

• Cyprine: Norway; New Jersey, USA; South Africa; Iceland

• Xanthite: New York, USA

• Solairite: Quebec, Canada

• Wiluite: Siberia, Russia

Idocrase Stone Price & Value

The priciest type of idocrase gems are faceted, though their prices vary by color, quality and size. The general price-per-carat rates for high-quality faceted idocrase gems by color:

• Reddish-orange: $30 to $100 per carat (1-10 cts)

• Orange-yellow: $60 to $160 per carat (1-10 cts)

• Yellow-green: $80 to $240 per carat (1-10 cts)

• Reddish-purple: $540 to $1,550 per carat (1-10 cts)

Faceted solairite vesuvianites are often in the top price tier around $780 per carat.

Cabochons are much more affordable, generally around $5 per carat. Tumbled stones are similarly budget-friendly, around $5 to $10 each.

The most common jewelry available are cabochon idocrase rings, which range from around $10 to $70 per carat.

Idocrase Care and Maintenance

Luckily, gemstone care for idocrase is pretty easy. Still, we recommend protective settings for idocrase jewelry like rings.

The main consideration is the fairly low hardness, so keep it away from harder gemstones and objects. Also keep idocrase from:

• Mechanical cleaning systems

• Rapid temperature changes

• Prolonged direct heat

• Harsh chemicals

Clean idocrase with warm water, mild soap, and a soft toothbrush. Rinse off soap residue and dry it with a soft, microfiber cloth.

Ready to Kickstart An Idocrase Craze?

Though idocrase hasn’t become a jewelry craze yet, collector’s have adored the stone’s unique origins, colors, and history for years. This is a perfectly unique gem for any collector or casual gem lover!

Buy idocrase gemstones today!