Hielscherite is a very rare member of the ettringite group typically found in volcanic xenoliths within the Eifel region of Germany. It commonly forms delicate, needle-like hexagonal prisms that can be difficult to distinguish from ettringite without chemical analysis. Collectors prize it primarily for its extreme rarity and unique geological occurrence.
Is this hielscherite?
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 hielscherite with a known reference. Hielscherite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hielscherite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hielscherite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular to prismatic crystals.
Often confused with
Hielscherite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside hielscherite
Minerals reported to co-occur with hielscherite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₆Ca₃Si₂O₄(SO₄)₃(OH)₁₂·26H₂O
- Mohs hardness
- 2.5
- Density
- 1.79 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular to Prismatic Crystals
- Cleavage
- Perfect On {10-10}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Xenoliths in Volcanic Rocks
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find hielscherite
Classic worldwide localities
- Ettringen, Germany
- Mayen, Germany
Field-hunting tip
Look in xenoliths in volcanic rocks country — that is the host setting where hielscherite typically forms. If you start seeing ettringite, thaumasite, afwillite in float, you are in the right ground. Field specimens usually show a acicular to prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hielscherite?+
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How much is hielscherite worth?+
What rocks look like hielscherite?+
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Find hielscherite on the map
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