Identification guide · Minerals
How to Identify Sodalite
Sodalite is usually blue, blue with white veins, and gray-blue with a vitreous luster and is translucent. It has a Mohs hardness of 5.5. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Its streak is white. It is most often confused with Chalcedony, Diopside, and Labradorite; the tests below separate them.
Sodalite identification checklist
| Color | Blue, Blue with white veins, Gray-Blue | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Translucent | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 5.5 | It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. |
| Streak | White | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Poor | |
| Fracture | Conchoidal | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 2.3 | Ordinary rock-like heft (specific gravity about 2.3), similar to quartz. |
| Crystal system | Cubic |
Extra tests for Sodalite
Glass check. Sodalite shares a glassy luster and conchoidal fracture with man-made glass. Glass sits near Mohs 5.5 and often contains round gas bubbles, so a hardness test and a hand lens separate them.
Sodalite look-alikes and how to tell them apart
Chalcedony is harder (Mohs 6.5–7) than Sodalite (Mohs 5.5), so Chalcedony will scratch Sodalite and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Sodalite vs Chalcedony →
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Sodalite vs Diopside →
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Sodalite vs Labradorite →
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
Field tips
- Check whether the specimen's color and texture match typical Sodalite examples.
- Use hardness, streak, luster, grain size, and locality together; no single trait is enough for every specimen.
Sodalite identification FAQ
How can you tell if a rock is Sodalite?
Check the color (blue, blue with white veins, and gray-blue), the vitreous luster, a Mohs hardness of 5.5 and a white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Sodalite?
Sodalite has a Mohs hardness of 5.5. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
What is the difference between Sodalite and Chalcedony?
Sodalite (Mohs 5.5, vitreous luster) and Chalcedony (Mohs 6.5–7, waxy to vitreous luster) look alike, but hardness, streak and heft usually separate them. See the full Sodalite vs Chalcedony comparison for a side-by-side table.
Is Sodalite worth anything?
Entry-level Sodalite specimens sell for around $5, typical collector pieces about $20, and premium examples $100 or more depending on size, quality and locality.
What color is Sodalite?
Sodalite is most often blue, blue with white veins, and gray-blue. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
