Blue amphibole refers to members of the glaucophane-riebeckite series, typically found in blueschist metamorphic terrains. It is easily identified by its distinctive blue color and often fibrous or needle-like habit. Collectors must exercise extreme caution due to its potential asbestiform nature.
Is this blue amphibole?
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 blue amphibole with a known reference. Blue Amphibole sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Blue Amphibole leaves a white to light blue streak.
- 3Read the lusterHold the specimen under a strong light. Blue Amphibole typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-gray, lavender-blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, acicular, or prismatic crystals.
Often confused with
Blue Amphibole vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Tourmaline is the harder of the two (Mohs 7-7.5 vs. 5-6); streak differs — Blue Amphibole leaves white to light blue, Tourmaline leaves white.
How to tell apart: Streak differs — Blue Amphibole leaves white to light blue, Actinolite leaves white; luster reads vitreous on Blue Amphibole and vitreous to silky on Actinolite.
How to tell apart: Dumortierite is the harder of the two (Mohs 7-8.5 vs. 5-6); streak differs — Blue Amphibole leaves white to light blue, Dumortierite leaves white.
Often found alongside blue amphibole
Minerals reported to co-occur with blue amphibole. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂(Fe²⁺₃Fe³⁺₂)Si₈O₂₂(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.0-3.4 g/cm³
- Streak
- White to Light Blue
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Acicular, Or Prismatic Crystals
- Cleavage
- Perfect in 2 Directions
- Rarity
- Common
- Uses
- Collector
- Host rock
- Metamorphic Schists and Blueschist Facies
- Typical price
- $10-50 per specimen depending on fiber density
Where rockhounds find blue amphibole
1 mapped spotsClassic worldwide localities
- Western Australia
- South Africa
- California, USA
- Japan
- Switzerland
Field-hunting tip
Look in metamorphic schists and blueschist facies country — that is the host setting where blue amphibole typically forms. If you start seeing quartz, epidote, chlorite in float, you are in the right ground. Field specimens usually show a fibrous, acicular, or prismatic crystals habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in West Virginia — start trip planning there.
Common questions
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Find blue amphibole on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
