Glauberite is a soluble sulfate mineral that typically forms as wedge-shaped, tabular crystals within evaporite sequences. It is notably unstable in water, where it may alter to gypsum or other sulfate minerals, making it a challenging species to preserve in humid environments. Look for its characteristic thin, platy crystal habits in saline lake deposits.
Is this glauberite?
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 glauberite with a known reference. Glauberite 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. Glauberite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Glauberite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellow, gray, pale brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, wedge-shaped crystals.
Often confused with
Glauberite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside glauberite
Minerals reported to co-occur with glauberite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Ca(SO₄)₂
- Mohs hardness
- 2.5-3
- Density
- 2.7-2.8 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Wedge-shaped Crystals
- Cleavage
- Perfect
- Rarity
- Common
- Uses
- Collector, Industrial Source of Sodium Sulfate
- Host rock
- Evaporite Deposits
- Typical price
- $10-50 for typical specimens
Where rockhounds find glauberite
4 mapped spotsClassic worldwide localities
- Borax Lake, California, USA
- Castilla, Spain
- Atacama Desert, Chile
- Hallstatt, Austria
- Tarapaca, Chile
Field-hunting tip
Look in evaporite deposits country — that is the host setting where glauberite typically forms. If you start seeing halite, thenardite, mirabilite in float, you are in the right ground. Field specimens usually show a tabular crystals, wedge-shaped crystals habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, New Mexico, North Dakota — start trip planning there.
Common questions
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Find glauberite on the map
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