Idocrase (vesuvianite): meaning, properties and care

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Idocrase, or vesuvianite, is a green to brown calcium silicate first described from Vesuvius. Its green variety, californite, is sold as “California jade”.

Key points

Colour	Green (olive, apple), yellow, brown, sometimes blue (cyprine) or nearly black
Mineral family	Silicate of calcium, magnesium, iron and aluminium (sorosilicate), tetragonal system
Mohs hardness	6.5
Density	About 3.4
Other names	Vesuvianite, californite (green variety), cyprine (blue variety)
Origin of the name	Vesuvius (Italy), where it was described in 1795 by Werner
Deposits	Vesuvius, the Pyrenees and Savoy (France), Quebec (Asbestos), California, Norway
Not to be confused with	Jade, serpentine, green grossular garnet

What is idocrase?

Idocrase is the old name for what mineralogists now call vesuvianite. It is a silicate of calcium, magnesium, iron and aluminium that also contains water and a little fluorine. Its crystals form small square prisms, olive green to brown, often striated.

It was described in 1795 by the German geologist Abraham Gottlob Werner, from samples from Monte Somma on Vesuvius: this is where its name comes from. It forms in limestone rocks transformed by heat, alongside garnet, diopside or wollastonite. It is also found in France (the Pyrenees, Savoy), in Quebec (the Jeffrey mine at Asbestos), in Italy, Norway and California.

The name “idocrase” is still often used by dealers and collectors in French-speaking countries. In the past it was also called “Vesuvius hyacinth” or, by mistake, chrysolite.

Californite and cyprine: two varieties

Two varieties have their own names:

Californite, a compact apple-green stone, resembles jade. Its cut pieces were long sold as “California jade”, although it is a different material from true jade.
Cyprine, blue, owes its colour to traces of copper. It is rare and comes in particular from Norway.

To tell it apart from jade, see the page jade: jade is tougher and has a fibrous structure.

Traditional symbolism

Idocrase is a stone rarely mentioned in ancient traditions, and its use in crystal healing is recent. In modern books it is associated with transitions, growth and a connection with nature, through the image of its green colour and volcanic origin. It is also called a stone of balance between the urge to move and the wish to stay grounded.

These meanings are only symbols, with no proven effect on health or fate. They serve as a point of support for a personal ritual: celebrating a new stage, marking a decision.

Traditional correspondences

Area	Common association
Chakra	Heart most often; some authors cite the solar plexus
Element	Earth
Signs	No agreement: Taurus and Capricorn are sometimes cited

For the heart chakra, see the page heart chakra. For stones linked with a turning point in life, see new beginnings.

How to use it

As a pendant or ring: with a hardness of 6.5, it handles reasonable daily wear.
As a pocket stone: as a small tumbled stone, as a reminder during a life change.
On an altar or shelf: as a raw crystal, green to brown, to evoke nature and the earth.
As a gift: for a move, the start of a project or a new stage.

For setting ideas, see the guide to gemstone jewellery.

Care and cleansing

Cleaning: lukewarm water, mild soap, a soft brush, then dry with a cloth.
Acids: to be avoided, as vesuvianite is partly soluble in hydrochloric acid and can be attacked by other strong acids.
Sun: harmless as far as known, in moderation.
Salt: unnecessary and bad for settings.
Symbolic cleansing: smoke, moonlight, or placing it on selenite. See our cleansing guide.

As with any stone that is softer than quartz, avoid storing it in contact with quartz or any harder stone.

Recognising genuine idocrase and avoiding confusion

Several green materials resemble it:

Jade (jadeite or nephrite): tougher, and a different species. The name “California jade” applied to californite is therefore misleading.
Serpentine, soft, sometimes dyed to imitate jade.
Green grossular garnet, another calcium silicate, often found with idocrase in the same rock.

Nothing shows that idocrase is commonly dyed, but ask for the exact name: “jade” on its own on a listing should make you vigilant. The gemstone glossary helps you understand trade names.

How to choose

For jewellery, look for a compact green californite, free of cracks, with an even polish. For collecting, well-formed crystals still in their host rock are the most sought after. Prices remain moderate for small stones; fine cyprine pieces or collector crystals cost more.

It pairs easily with other greens, such as peridot or epidote, or with a light stone.