Short answer: sodalite is a royal blue mineral, often streaked with white veins, named for the sodium it contains. It is softer than quartz, 5.5 to 6 on the Mohs scale, and is cut into beads, spheres, towers and carvings. It is often confused with lapis lazuli, but it rarely contains gold-colored pyrite and leaves a white streak.
What is sodalite?
Sodalite is a sodium aluminum silicate with chlorine, Na8(Al6Si6O24)Cl2. Mineralogists place it with the feldspathoids, minerals that form in place of feldspar in rocks that are low in silica and rich in sodium. It belongs to the sodalite group, alongside lazurite, the blue mineral that gives lapis lazuli its color.
It is light for a stone, with a specific gravity of about 2.3, a little lighter than quartz. It is fairly hard but brittle, and it has six directions of poor cleavage that can show as faint internal cracks.
Why is sodalite blue with white veins?
The deep blue is the mineral itself. The white veins and patches are other minerals that grew alongside it in the same rock, most often calcite and related light-colored minerals. Material that is evenly blue is set aside for jewelry and cabochons. Material with more white veining is used for carvings, spheres, towers, tumbled stones and decorative facing.
Sodalite is not always blue. It also occurs gray, yellow, green and pink, but blue is what the trade means by the name.
Sodalite and ultraviolet light
Most sodalite fluoresces orange under ultraviolet light, which surprises people who expect a blue stone to glow blue. A variety called hackmanite goes further: it is tenebrescent, meaning it changes color when exposed to sunlight or ultraviolet light, then slowly fades back in the dark. It is one of the most interesting minerals to show under a UV flashlight.
Where does sodalite come from?
Sodalite was first described in 1811 from the Ilimaussaq complex in Greenland. It became an important ornamental stone after large deposits of fine material were found in Ontario, Canada, in 1891. Notable sources include Bancroft, Ontario, home of the Princess Sodalite Mine, and Mont-Saint-Hilaire in Quebec, with others in Bolivia and in the United States at Litchfield, Maine and Magnet Cove, Arkansas.
People traded for it long before that: the Caral culture of ancient Peru traded for sodalite from the Andean plateau.
How is sodalite identified?
A few simple properties separate sodalite from other blue stones.
- It is light for its size, with a specific gravity of about 2.3, lighter than quartz and noticeably lighter than lapis lazuli.
- It leaves a white streak on unglazed porcelain.
- It shows faint internal cracks along its six directions of poor cleavage.
- It usually fluoresces orange under ultraviolet light.
- It is soluble in strong acids, which is why acids should never be used to clean it.
How is sodalite used?
The more evenly blue material is cut into cabochons and beads for jewelry. Lesser material, with more white veining, is used for carvings, spheres, towers, tumbled stones, and as decorative facing and inlay. The large Canadian deposits found in 1891 made sodalite widely available as an ornamental stone, and Ontario's Bancroft area is still known for it.
What is sodalite traditionally associated with?
In modern crystal traditions, sodalite is associated with logic, clear thinking, calm communication and truthfulness. It is often described as a stone of rational thought, the counterpart to more intuitive blue stones. In chakra traditions it is linked with the throat and third eye chakras.
These are traditional associations and beliefs. They are part of why people choose sodalite, not properties you can measure in the mineral.
Raw, tumbled and polished sodalite
Raw sodalite is a dull to greasy blue rock, often with white or gray patches. Polishing deepens the color and brings up a soft, vitreous shine. Tumbled stones, palm stones and worry stones are popular because the white veining makes each one different. Spheres and towers show the veins as flowing patterns across the surface.
Sodalite jewelry
Evenly blue sodalite is cut into cabochons and beads for necklaces, bracelets and earrings. At 5.5 to 6 on the Mohs scale it is softer than quartz and can scratch with daily wear, so beaded bracelets and rings will show wear sooner than pendants.
How do you care for sodalite?
- Clean it with lukewarm water and mild soap, then dry it.
- Avoid acids and harsh chemicals. Sodalite is soluble in strong acids, and the calcite in its veins reacts with them.
- Keep it apart from harder stones that can scratch it.
- Avoid hard knocks, since it is brittle.
Sodalite vs lapis lazuli: how do you tell them apart?
The two look alike in a photograph, but they are easy to separate in hand.
- Gold flecks: lapis lazuli usually contains specks of gold-colored pyrite. Sodalite rarely does.
- Color: sodalite is a royal or indigo blue. Lapis tends toward a brighter ultramarine.
- Veins: sodalite usually shows white veins and patches. Lapis more often shows white calcite patches together with gold pyrite.
- Streak: rub the stone on unglazed white porcelain. Sodalite leaves a white streak. Lapis lazuli leaves a light blue one.
- Weight: sodalite is lighter than lapis for the same size.
How can you tell real sodalite?
Blue stones are often imitated with dyed material, such as white howlite or magnesite dyed blue, which can look convincing. Dye tends to collect in cracks and pits, and it can rub off on a cotton swab with a little acetone. Natural sodalite has color that runs through the stone, with natural white veining, and it often glows orange under ultraviolet light.
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Frequently asked questions
Is sodalite the same as lapis lazuli?
No. They are related, both belonging to the sodalite group of minerals, but they are different stones. Lapis lazuli is a rock colored by lazurite, usually with gold pyrite flecks. Sodalite is a single mineral, rarely contains pyrite and leaves a white streak.
Is sodalite water safe?
Brief contact with water is fine, and lukewarm water with mild soap is a safe way to clean it. Do not soak it for long periods, and keep it away from acids and harsh cleaners.
What is sodalite traditionally associated with?
In crystal traditions it is associated with logic, clear thinking and calm communication, and with the throat and third eye chakras. These are traditional meanings rather than measurable properties.
Why does my sodalite glow orange under UV light?
Most sodalite fluoresces orange under ultraviolet light. It is a natural property of the mineral and a good sign that the stone is real rather than dyed.
Is sodalite expensive?
Ornamental sodalite is widely available and affordable. Evenly colored, deep blue material and transparent faceting-grade sodalite are scarcer and cost more.
What is hackmanite?
Hackmanite is a variety of sodalite that is tenebrescent: it changes color when exposed to sunlight or ultraviolet light, typically to violet-red or green, and the color then fades back toward white. It is a favorite among collectors who use UV flashlights.
Sources
- Wikipedia, Sodalite: https://en.wikipedia.org/wiki/Sodalite
- Wikipedia, Hackmanite: https://en.wikipedia.org/wiki/Hackmanite
- Geology.com, Sodalite: https://geology.com/minerals/sodalite.shtml
- Wikipedia, Fluorescence: https://en.wikipedia.org/wiki/Fluorescence