Identification guide · Minerals
How to Identify Hauyne
Hauyne appears as small, rounded to dodecahedral crystals, typically a rich cornflower to violet blue, though gray and colorless material also occurs, with a vitreous to slightly greasy luster and a pale blue streak. Hardness of 5.5 to 6 and a lack of the strong crystal faces typical of garnet, another dodecahedral mineral, help with identification, along with hauyne's much lower density. Its close resemblance to lazurite and sodalite means confirming hauyne often depends on its volcanic host rock and crystal form, since all three can share a similar blue color.
Hauyne identification checklist
| Color | Blue, Sky blue, Greenish blue, White | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous to greasy | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Transparent to translucent | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 5.5–6 | It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. |
| Streak | Pale blue | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Distinct dodecahedral | |
| Fracture | Conchoidal to uneven | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 2.4–2.5 | Ordinary rock-like heft (specific gravity about 2.45), similar to quartz. |
| Crystal system | Isometric |
Extra tests for Hauyne
Glass check. Hauyne 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.
Hauyne look-alikes and how to tell them apart
Both sit near Mohs 5.5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hauyne vs Diopside →
Hauyne is harder (Mohs 5.5–6) than Calcite (Mohs 3), so Hauyne will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Hauyne vs Calcite →
Both sit near Mohs 5.5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hauyne vs Albite →
Both sit near Mohs 5.5–6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
Hauyne identification FAQ
How can you tell if a rock is Hauyne?
Check the color (blue, sky blue, greenish blue, and white), the vitreous to greasy luster, a Mohs hardness of 5.5–6 and a pale blue streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Hauyne?
Hauyne has a Mohs hardness of 5.5–6. 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 Hauyne and Diopside?
Hauyne (Mohs 5.5–6, vitreous to greasy luster) and Diopside (Mohs 5.5–6.5, vitreous luster) look alike, but hardness, streak and heft usually separate them. See the full Hauyne vs Diopside comparison for a side-by-side table.
Is Hauyne worth anything?
Entry-level Hauyne specimens sell for around $2, typical collector pieces about $20, and premium examples $150 or more depending on size, quality and locality.
What color is Hauyne?
Hauyne is most often blue, sky blue, greenish blue, and white. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
