Haüyne is a striking blue sulfate mineral most famous for its vivid, neon-blue color found in the Eifel volcanic region of Germany. It typically forms small dodecahedral crystals within alkaline igneous rocks and is highly prized by collectors for its brilliance and rarity. Collectors should look for sharp, gemmy crystals, though high-quality specimens are often very small.
Is this haüyne?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch haüyne with a known reference. Haüyne sits at Mohs 5.5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: slightly bluish to colorless.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: blue, green, yellow, white, colorless, red, gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: crystalline, euhedral crystals, twinning common.
Often confused with
Haüyne vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Haüyne leaves slightly bluish to colorless, Sodalite leaves white.
How to tell apart: Streak differs, so Haüyne leaves slightly bluish to colorless, Lazurite leaves bright blue.
How to tell apart: Streak differs, so Haüyne leaves slightly bluish to colorless, Nosean leaves bluish white.
Often found alongside haüyne
Minerals reported to co-occur with haüyne. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃Ca(Si₃Al₃)O₁₂(SO₄)
- Mohs hardness
- 5.5-6
- Density
- 2.44-2.50 g/cm³
- Streak
- Slightly bluish to colorless
- Luster
- Vitreous to greasy
- Transparency
- Transparent to translucent
- Crystal system
- Cubic
- Crystal habit
- Crystalline, euhedral crystals, twinning common
- Cleavage
- {110}, distinct
- Rarity
- Rare
- Uses
- Collector, Gemstone
- Host rock
- In phonolites and related leucite- or nepheline-rich igneous rocks; less commonly in nepheline-free extrusives
Where rockhounds find haüyne
Classic worldwide localities
- Winnett, Petroleum Co., Montana, and in the Edwards mine, St. Lawrence Co., New York, USA
- Mendig, Mayen, in the Eifel district, Germany
- Niangniang Shan complex, Nanjing, Jiangsu Province, China
- Smaller island of Taiarupu, Tahiti
Field-hunting tip
Where it forms: In phonolites and related leucite- or nepheline-rich igneous rocks; less commonly in nepheline-free extrusives. If you start seeing nepheline, leucite, titanian andradite in float, you are in the right ground. Typical habit: crystalline, euhedral crystals, twinning common. Train your eye for that shape before scanning the outcrop.
Common questions
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Find haüyne on the map
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