Selenite is a crystalline variety of gypsum characterized by its soft, pearly luster and perfect cleavage into thin, flexible sheets. It is famously found in massive, giant crystal structures in karst cave systems and as fibrous 'Satin Spar' in sedimentary layers.
Is this selenite?
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 selenite with a known reference. Selenite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Selenite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Selenite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, gray, peach, honey.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: bladed crystals, fibrous, tabular, selenite roses.
Often confused with
Selenite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Selenite is noticeably harder (Mohs 2 vs. 1).
How to tell apart: Calcite is the harder of the two (Mohs 3 vs. 2); luster reads pearly on Selenite and vitreous on Calcite.
How to tell apart: Anhydrite is the harder of the two (Mohs 3.5 vs. 2); luster reads pearly on Selenite and vitreous on Anhydrite.
Often found alongside selenite
Minerals reported to co-occur with selenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaSO₄·2H₂O
- Mohs hardness
- 2
- Density
- 2.3 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Bladed Crystals, Fibrous, Tabular, Selenite Roses
- Cleavage
- Perfect in One Direction
- Fluorescence
- Often Fluoresces White or Yellow Under LW UV
- Rarity
- Common
- Uses
- Collector, Decorative, Lapidary
- Host rock
- Sedimentary Evaporite Deposits, Hydrothermal Veins, Clay Beds
- Typical price
- $5-50 for small specimens, $100-500 for large clusters
Where rockhounds find selenite
24 mapped spotsClassic worldwide localities
- Naica Mine, Mexico
- Morocco
- Oklahoma, USA
- Australia
- Spain
U.S. states with selenite
Each link opens a state-specific list of mapped rockhounding spots that produce selenite.
Field-hunting tip
Look in sedimentary evaporite deposits, hydrothermal veins, clay beds country — that is the host setting where selenite typically forms. If you start seeing calcite, halite, sulfur in float, you are in the right ground. Field specimens usually show a bladed crystals, fibrous, tabular, selenite roses habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, North Dakota, Oklahoma — start trip planning there.
Common questions
How do you identify selenite?+
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Find selenite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
