Cebollite is a rare calcium aluminum silicate mineral known for its distinct fibrous or needle-like appearance. It is primarily found as a secondary alteration product in igneous rocks, specifically in the Gunnison County area of Colorado where it was first discovered.
Is this cebollite?
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 cebollite with a known reference. Cebollite sits at Mohs 5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Cebollite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Cebollite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, grayish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: fibrous, massive, or radiating aggregates.
Often confused with
Cebollite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside cebollite
Minerals reported to co-occur with cebollite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Al₂Si₃O₁₂(OH)₂
- Mohs hardness
- 5
- Density
- 2.9-3.0 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Fibrous, Massive, Or Radiating Aggregates
- Cleavage
- Distinct in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Altered Melilite-bearing Igneous Rocks
- Typical price
- $20-100 per specimen
Where rockhounds find cebollite
Classic worldwide localities
- Cebolla Creek, Gunnison County, Colorado, USA
Field-hunting tip
Look in altered melilite-bearing igneous rocks country — that is the host setting where cebollite typically forms. If you start seeing calcite, melilite, diopside in float, you are in the right ground. Field specimens usually show a fibrous, massive, or radiating aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cebollite?+
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How much is cebollite worth?+
What rocks look like cebollite?+
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Find cebollite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
