Thermonatrite is a rare, unstable carbonate mineral typically found as a dehydration product of natron in arid, saline lake environments. It is rarely found in distinct crystals, appearing most often as white, chalky crusts or powdery efflorescences on dry lake beds. Collectors should handle specimens carefully, as it is highly soluble in water and prone to atmospheric degradation.
Is this thermonatrite?
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 thermonatrite with a known reference. Thermonatrite 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: white, colorless, grayish yellow, grayish, yellowish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crusts, efflorescences, massive aggregates.
Often confused with
Thermonatrite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside thermonatrite
Minerals reported to co-occur with thermonatrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂CO₃·H₂O
- Mohs hardness
- 1-1.5
- Density
- 2.255 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Crusts, efflorescences, massive aggregates
- Cleavage
- On {100}, difficult
- Rarity
- Common
- Uses
- Collector, Geological indicator
- Host rock
- Typically on soils and deposited from saline lakes; uncommon in volcanic fumaroles; in hydrothermal veins related to carbonatites
Where rockhounds find thermonatrite
Classic worldwide localities
- Borax Lake, Lake Co., and at Deep Spring Lake, Inyo Co., California, USA
- Point of Rocks, east of Springer, Colfax Co., New Mexico, USA
- Vesuvius, Campania, Italy
- Kola Peninsula, on Mts. Rasvumchorr and Kukisvumchorr, and in the Vuonnemiok River valley, Khibiny massif, Russia
- Mt. Alluaiv, Lovozero massif, Russia
- Kovdor massif, Russia
Field-hunting tip
Where it forms: Typically on soils and deposited from saline lakes; uncommon in volcanic fumaroles; in hydrothermal veins related to carbonatites. If you start seeing trona, natron, halite in float, you are in the right ground. Typical habit: crusts, efflorescences, massive aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify thermonatrite?+
Where is thermonatrite found?+
What rocks look like thermonatrite?+
What minerals are found with thermonatrite?+
What kind of rock does thermonatrite form in?+
What is thermonatrite used for?+
Find thermonatrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
