Hydroglauberite is a rare hydrated sulfate mineral that forms in arid evaporite environments. It is chemically similar to glauberite but contains essential water in its structure, making it highly sensitive to changes in humidity and temperature. Collectors typically find it as small, fragile tabular crystals associated with other salt minerals.
Is this hydroglauberite?
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 hydroglauberite with a known reference. Hydroglauberite sits at Mohs 2-3, 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: silky in aggregates.
- 4Match the color rangeCompare against the expected color range: snow white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Hydroglauberite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads silky in aggregates on Hydroglauberite and vitreous to waxy, pearly on {001} cleavage surfaces on Glauberite.
How to tell apart: Luster reads silky in aggregates on Hydroglauberite and subvitreous, pearly on {010} cleavages, silky if fibrous on Gypsum.
Often found alongside hydroglauberite
Minerals reported to co-occur with hydroglauberite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₁₀Ca₃(SO₄)₈·6H₂O
- Mohs hardness
- 2-3
- Density
- 1.510 g/cm³
- Colors
- Streak
- White
- Luster
- Silky in aggregates
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular crystals
- Cleavage
- Three noted, one of which is parallel to elongation
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon alteration product of glauberite
Where rockhounds find hydroglauberite
Classic worldwide localities
- San Simon, Cochise Co., Arizona, USA
- Kushkanatau salt deposit, lower Amu Darya River, Kara-Kalpakia, Uzbekistan
- Cesano geothermal field, Latium, Italy
- Kalkberg, near Lüneburg, Lower Saxony, Germany
- Salar de Pintados, near La Guaica, Tarapacá, Chile
Field-hunting tip
Where it forms: An uncommon alteration product of glauberite. If you start seeing glauberite, halite, mirabilite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hydroglauberite?+
Where is hydroglauberite found?+
What rocks look like hydroglauberite?+
What minerals are found with hydroglauberite?+
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What is hydroglauberite used for?+
Find hydroglauberite on the map
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