Stellerite is a distinct zeolite mineral that often forms beautiful, fan-shaped or radiating aggregates of tabular crystals. It is frequently found lining cavities in volcanic rocks and is often visually confused with stilbite, though it typically lacks the prominent sheaf-like curvature found in the latter.
Is this stellerite?
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 stellerite with a known reference. Stellerite sits at Mohs 4.5-5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Stellerite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Stellerite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish, pinkish, orange.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: radiating clusters, fan-shaped aggregates, tabular crystals.
Often confused with
Stellerite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside stellerite
Minerals reported to co-occur with stellerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄(Al₈Si₂₈O₇₂)·28H₂O
- Mohs hardness
- 4.5-5
- Density
- 2.12-2.15 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Radiating Clusters, Fan-shaped Aggregates, Tabular Crystals
- Cleavage
- Perfect On {010}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Cavities in Basalt and Andesite Volcanic Rocks
- Typical price
- $10-150 thumbnail, $50-500 cabinet specimen
Where rockhounds find stellerite
1 mapped spotsClassic worldwide localities
- Commander Islands, Russia
- Hokkaido, Japan
- Cape Blomidon, Nova Scotia, Canada
- Iceland
- Skye, Scotland
Field-hunting tip
Look in cavities in basalt and andesite volcanic rocks country — that is the host setting where stellerite typically forms. If you start seeing heulandite, stilbite, quartz in float, you are in the right ground. Field specimens usually show a radiating clusters, fan-shaped aggregates, tabular crystals habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah — start trip planning there.




