Ferrierite-K is a rarer member of the zeolite group often found as thin, bladed crystals or radiating sprays within volcanic cavities. It is most easily identified by its distinct bladed habit and association with other secondary zeolites in basaltic host rocks.
Is this ferrierite-k?
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 ferrierite-k with a known reference. Ferrierite-K sits at Mohs 3-3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Ferrierite-K leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ferrierite-K typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish, tan.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: bladed crystals, radial aggregates, fibrous.
Often confused with
Ferrierite-K vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside ferrierite-k
Minerals reported to co-occur with ferrierite-k. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (K₂,Na₂,Mg,Ca)₃Si₁₈Al₃O₄₂·18H₂O
- Mohs hardness
- 3-3.5
- Density
- 2.14 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Bladed Crystals, Radial Aggregates, Fibrous
- Cleavage
- Perfect On {100}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Basaltic Volcanic Rocks, Vugs and Vesicles
- Typical price
- $15-60 for small mineral specimens
Where rockhounds find ferrierite-k
Classic worldwide localities
- Kamloops, British Columbia, Canada
- Agoura, California, USA
- Vicentina, Italy
- Japan
Field-hunting tip
Look in basaltic volcanic rocks, vugs and vesicles country — that is the host setting where ferrierite-k typically forms. If you start seeing calcite, quartz, heulandite in float, you are in the right ground. Field specimens usually show a bladed crystals, radial aggregates, fibrous habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferrierite-k?+
Where is ferrierite-k found?+
How much is ferrierite-k worth?+
What rocks look like ferrierite-k?+
What minerals are found with ferrierite-k?+
What kind of rock does ferrierite-k form in?+
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Find ferrierite-k on the map
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