Gobbinsite is a rare zeolite mineral that typically forms small, white pseudocubic crystals within cavities of basaltic rocks. It is best identified through its characteristic interpenetrant twinning and association with other zeolites like phillipsite.
Is this gobbinsite?
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 gobbinsite with a known reference. Gobbinsite sits at Mohs 4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Gobbinsite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Gobbinsite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: pseudocubic crystals, aggregates, interpenetrant twins.
Often confused with
Gobbinsite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside gobbinsite
Minerals reported to co-occur with gobbinsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₄CaAl₆Si₁₀O₃₂·12H₂O
- Mohs hardness
- 4
- Density
- 2.14 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Pseudocubic Crystals, Aggregates, Interpenetrant Twins
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Basaltic Volcanic Rocks, Amygdaloidal Cavities
- Typical price
- $20-100 per specimen
Where rockhounds find gobbinsite
Classic worldwide localities
- Gobbins, Northern Ireland
- Mount Semeru, Indonesia
- Iceland
- Faeroe Islands
Field-hunting tip
Look in basaltic volcanic rocks, amygdaloidal cavities country — that is the host setting where gobbinsite typically forms. If you start seeing phillipsite, chabazite, calcite in float, you are in the right ground. Field specimens usually show a pseudocubic crystals, aggregates, interpenetrant twins habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find gobbinsite on the map
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