Nestolaite is a rare calcium selenite that forms light violet flattened to acicular crystals. It is a secondary mineral in the oxidized zone of a uranium deposit of the Colorado Plateau type. Associated minerals include cobaltomenite, gypsum and metarossite. It was first described from Little Eva mine, Yellow Cat district, Grand County, Utah, USA.
Is this nestolaite?
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 nestolaite with a known reference. Nestolaite sits at Mohs 2.5, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: light violet.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: flattened to acicular crystals.
Often confused with
Nestolaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside nestolaite
Minerals reported to co-occur with nestolaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaSeO₃·H₂O
- Mohs hardness
- 2.5
- Density
- 3.18 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Flattened to acicular crystals
- Cleavage
- Perfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral in the oxidized zone of a uranium deposit of the Colorado Plateau type
Where rockhounds find nestolaite
Classic worldwide localities
- Little Eva mine, Yellow Cat district, Grand County, Utah, USA
Field-hunting tip
Where it forms: A secondary mineral in the oxidized zone of a uranium deposit of the Colorado Plateau type. If you start seeing cobaltomenite, gypsum, metarossite in float, you are in the right ground. Typical habit: flattened to acicular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify nestolaite?+
Where is nestolaite found?+
Is nestolaite safe to handle?+
What rocks look like nestolaite?+
What minerals are found with nestolaite?+
What kind of rock does nestolaite form in?+
What is nestolaite used for?+
Find nestolaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
