Heidornite is a rare borate-sulfate mineral typically found in marine evaporite sequences. It usually forms small, colorless to white prismatic crystals and is primarily a target for advanced systematic mineral collectors specializing in borate species.
Is this heidornite?
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 heidornite with a known reference. Heidornite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Heidornite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Heidornite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellowish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, sometimes tabular.
Often confused with
Heidornite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside heidornite
Minerals reported to co-occur with heidornite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Ca₃Cl(SO₄)₂B₅O₈(OH)₂
- Mohs hardness
- 4
- Density
- 3.01 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Sometimes Tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Evaporite Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find heidornite
Classic worldwide localities
- Germany
- United States
Field-hunting tip
Look in evaporite deposits country, the host setting where heidornite typically forms. If you start seeing halite, sylvite, anhydrite in float, you are in the right ground. Field specimens usually show a prismatic crystals, sometimes tabular habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find heidornite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
