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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 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
- Imperfect on {10*0}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- volcanic fumaroles
Where rockhounds find natroaphthitalite
Classic worldwide localities
- Mount Vesuvius, Italy
- Tolbachik volcano, Russia
Field-hunting tip
Where it forms: volcanic fumaroles. If you start seeing aphthitalite, thenardite, sylvite in float, you are in the right ground. Typical habit: tabular crystals, crusts, granular masses. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify natroaphthitalite?+
Where is natroaphthitalite found?+
What rocks look like natroaphthitalite?+
What minerals are found with natroaphthitalite?+
What kind of rock does natroaphthitalite form in?+
What is natroaphthitalite used for?+
Find natroaphthitalite on the map
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