Trona is a primary ore of sodium carbonate, commonly forming as evaporite deposits in arid lake beds. It is easily recognized by its bladed, often translucent crystal clusters, though it can also appear as massive or efflorescent crusts that crumble if exposed to excessive humidity.
Is this trona?
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 trona with a known reference. Trona sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Trona leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Trona typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, gray, yellow, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, fibrous masses, efflorescent crusts.
Often confused with
Trona vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside trona
Minerals reported to co-occur with trona. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃(CO₃)(HCO₃)·2H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.14 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Fibrous Masses, Efflorescent Crusts
- Cleavage
- Perfect
- Rarity
- Common
- Uses
- Industrial, Collector
- Host rock
- Evaporite Deposits in Alkaline Lake Beds
- Typical price
- $10-50 per specimen
Where rockhounds find trona
Classic worldwide localities
- Green River Basin, Wyoming, USA
- Searles Lake, California, USA
- Lake Magadi, Kenya
- Fezzan, Libya
Field-hunting tip
Look in evaporite deposits in alkaline lake beds country — that is the host setting where trona typically forms. If you start seeing halite, gaylussite, shortite in float, you are in the right ground. Field specimens usually show a bladed crystals, fibrous masses, efflorescent crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find trona on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
