Celestine is a strontium sulfate mineral best known for its stunning, pale sky-blue crystals found in sedimentary vugs and geodes. Collectors typically look for its characteristic orthorhombic tabular habits, often associated with calcitic or dolomitic matrix.
Is this celestine?
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 celestine with a known reference. Celestine sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Celestine leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Celestine typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale blue, blue, gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular, prismatic, or pyramidal crystals, often in geodes.
Often confused with
Celestine vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside celestine
Minerals reported to co-occur with celestine. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SrSO₄
- Mohs hardness
- 3-3.5
- Density
- 3.95-3.97 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular, Prismatic, Or Pyramidal Crystals, Often in Geodes
- Cleavage
- Perfect in One Direction
- Fluorescence
- None to Faint Blue Under UV
- Rarity
- Common
- Uses
- Collector, Decorative, Industrial Source of Strontium
- Host rock
- Sedimentary Limestones and Evaporite Deposits
- Typical price
- $10-50 for small clusters, $100-500+ for large exhibition geodes
Where rockhounds find celestine
3 mapped spotsClassic worldwide localities
- Madagascar
- United States (Ohio)
- Mexico
- Italy
- Poland
Field-hunting tip
Look in sedimentary limestones and evaporite deposits country, the host setting where celestine typically forms. If you start seeing calcite, sulfur, fluorite in float, you are in the right ground. Field specimens usually show a tabular, prismatic, or pyramidal crystals, often in geodes habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Connecticut, Pennsylvania, Wisconsin. Start trip planning there.
Common questions
How do you identify celestine?+
Where is celestine found?+
Can I find celestine in the United States?+
How much is celestine worth?+
What rocks look like celestine?+
What minerals are found with celestine?+
What kind of rock does celestine form in?+
What is celestine used for?+
Find celestine on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
