Heklaite is a rare potassium sodium halide that forms colorless masses of intergrown micrometer-sized crystals. It is a sublimate precipitated around fumaroles emitting F-rich volcanic gases. Associated minerals include ralstonite, malladrite and hieratite. It was first described from Hekla central volcano, Eastern Volcanic Zone, South Iceland.
Is this heklaite?
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 heklaite with a known reference. Heklaite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: cololess, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: masses of intergrown micrometer-sized crystals.
Often confused with
Heklaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside heklaite
Minerals reported to co-occur with heklaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KNaSiF₆
- Mohs hardness
- 3
- Density
- 2.69 g/cm³
- Colors
- CololessWhite
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Masses of intergrown micrometer-sized crystals
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A sublimate precipitated around fumaroles emitting F-rich volcanic gases
Where rockhounds find heklaite
Classic worldwide localities
- Lava tubes in Hawaii, USA
- Hekla central volcano, Eastern Volcanic Zone, South Iceland
Field-hunting tip
Where it forms: A sublimate precipitated around fumaroles emitting F-rich volcanic gases. If you start seeing ralstonite, malladrite, hieratite in float, you are in the right ground. Typical habit: masses of intergrown micrometer-sized crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify heklaite?+
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What rocks look like heklaite?+
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Find heklaite on the map
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