Pectolite is best known for its acicular, radiating crystal clusters and as the primary component of the gemstone Larimar. It is commonly found in cavities of basaltic rocks, where it forms delicate fibrous sprays that can be very attractive for collectors.
Is this pectolite?
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 pectolite with a known reference. Pectolite 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. Pectolite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Pectolite typically shows a vitreous to silky luster.
- 4Match the color rangeCompare against the expected color range: white, gray, pale green, blue, yellowish.
- 5Look at form & habitCrystal system: triclinic. Typical habit: acicular, fibrous, radiating, or massive.
Often confused with
Pectolite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to silky on Pectolite and vitreous on Wollastonite.
How to tell apart: Luster reads vitreous to silky on Pectolite and vitreous on Natrolite.
How to tell apart: Prehnite is the harder of the two (Mohs 6-6.5 vs. 4.5-5); luster reads vitreous to silky on Pectolite and vitreous on Prehnite.
Often found alongside pectolite
Minerals reported to co-occur with pectolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₂Si₃O₈(OH)
- Mohs hardness
- 4.5-5
- Density
- 2.7-2.9 g/cm³
- Streak
- White
- Luster
- Vitreous to Silky
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Acicular, Fibrous, Radiating, Or Massive
- Cleavage
- Perfect in Two Directions
- Fluorescence
- Bright Orange to Yellow Under SW UV
- Rarity
- Uncommon
- Uses
- Collector, Lapidary
- Host rock
- Hydrothermal Veins in Mafic Volcanic Rocks and Nepheline Syenites
- Typical price
- $10-50 per specimen for typical clusters, higher for gem-grade Larimar
Where rockhounds find pectolite
2 mapped spotsClassic worldwide localities
- Dominican Republic
- New Jersey (USA)
- Quebec (Canada)
- Scotland
- Italy
Field-hunting tip
Look in hydrothermal veins in mafic volcanic rocks and nepheline syenites country — that is the host setting where pectolite typically forms. If you start seeing datolite, prehnite, calcite in float, you are in the right ground. Field specimens usually show a acicular, fibrous, radiating, or massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in California, New Jersey — start trip planning there.
Common questions
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Find pectolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
