Natron is a naturally occurring mixture of sodium carbonate decahydrate and other salts typically found in saline lake beds. It is highly unstable when exposed to dry air and will rapidly dehydrate into white, powdery thermonatrite. Collectors should store samples in airtight containers to prevent degradation.
Is this natron?
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 natron with a known reference. Natron sits at Mohs 1-1.5, 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: colorless, white, gray, yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: efflorescences, encrustations.
Often confused with
Natron vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside natron
Minerals reported to co-occur with natron. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂CO₃·10H₂O
- Mohs hardness
- 1-1.5
- Density
- 1.478 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Efflorescences, encrustations
- Cleavage
- Distinct on {001}; imperfect on {010}; in traces on {110}
- Rarity
- Common
- Uses
- Industrial, Historical preservation, Collector
- Host rock
- Formed on the margins around soda-rich lakes, or as a precipitate on lake bottoms during cold weather; as an efflorescence on lavas; rare in differentiated alkaline massifs
Where rockhounds find natron
Classic worldwide localities
- Noted in the Mt. Pisgah lava tubes, Mohave Desert, San Bernardino Co., California, and in Colorado, formed around artesian wells in the San Luis Valley, Costilla Co., USA
- Debrecen and Szeged districts, Hungary
- Salzburger Schacht, Untersberg, Austria
- Hall, Tirol, from Dürrnberg, near Hallein, and at Hallstatt, Austria
- Vesuvius, Campania, and Etna, Sicily, Italy
- Mt. Alluaiv, Lovozero massif, Kola Peninsula, Russia
Field-hunting tip
Where it forms: Formed on the margins around soda-rich lakes, or as a precipitate on lake bottoms during cold weather; as an efflorescence on lavas; rare in differentiated alkaline massifs. If you start seeing thermonatrite, trona, mirabilite in float, you are in the right ground. Typical habit: efflorescences, encrustations. Train your eye for that shape before scanning the outcrop.
Common questions
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What rocks look like natron?+
What minerals are found with natron?+
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Find natron on the map
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