Natroaphthitalite is a rare sodium-potassium sulfate typically found as a volcanic sublimate in fumarolic environments. Collectors should look for it as small tabular crystals or crusts coating volcanic rocks in active geothermal areas like Vesuvius.
Is this natroaphthitalite?
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 natroaphthitalite with a known reference. Natroaphthitalite 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. Natroaphthitalite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Natroaphthitalite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish, greenish.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, crusts, granular masses.
Often confused with
Natroaphthitalite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside natroaphthitalite
Minerals reported to co-occur with natroaphthitalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃K(SO₄)₂
- Mohs hardness
- 3
- Density
- 2.65 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Tabular Crystals, Crusts, Granular Masses
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Volcanic Fumaroles
- Typical price
- $20-100 per specimen
Where rockhounds find natroaphthitalite
Classic worldwide localities
- Mount Vesuvius, Italy
- Tolbachik volcano, Russia
Field-hunting tip
Look in volcanic fumaroles country, the host setting where natroaphthitalite typically forms. If you start seeing aphthitalite, thenardite, sylvite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, granular masses habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify natroaphthitalite?+
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Find natroaphthitalite on the map
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