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.

Hardness

2.5-3

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralcommon

Glauberite

Hardness: 2.5-3
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this glauberite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try 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.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Glauberite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Glauberite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, white, yellow, gray, pale brown.
5
Look at form & habit
Crystal 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
Colors: Colorless White Yellow Gray Pale Brown
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

5 mapped spots

Classic worldwide localities

Borax Lake, California, USA
Castilla, Spain
Atacama Desert, Chile
Hallstatt, Austria
Tarapaca, Chile

Field-hunting tip

Look in evaporite deposits country, 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.

Browse 5 U.S. spots for glauberite →

Common questions

How do you identify glauberite?+

Mohs hardness is 2.5-3. It typically shows a vitreous luster. The streak is white. Common colors include colorless, white, yellow, gray.

Where is glauberite found?+

Notable localities include Borax Lake, California, USA; Castilla, Spain; Atacama Desert, Chile; Hallstatt, Austria; Tarapaca, Chile.

Can I find glauberite in the United States?+

RockHoundR maps 5 glauberite rockhounding spots across 3 U.S. states. The top states are Utah, New Mexico, North Dakota.

How much is glauberite worth?+

Typical asking prices fall in the range of $10-50 for typical specimens. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like glauberite?+

Glauberite is most often confused with Gypsum, Anhydrite, Celestite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with glauberite?+

Glauberite commonly co-occurs with Halite, Thenardite, Mirabilite, Gypsum, Polyhalite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does glauberite form in?+

Glauberite typically forms in evaporite deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is glauberite used for?+

Glauberite is used in collector, industrial source of sodium sulfate.

Find glauberite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.