Ferro-ferri-holmquistite is a rare lithium-bearing amphibole occurring primarily as acicular or fibrous masses within lithium pegmatite contact zones. It is typically identified by its distinct violet-blue coloration and association with spodumene, though it is often difficult to distinguish from other amphiboles without chemical analysis.
Is this ferro-ferri-holmquistite?
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 ferro-ferri-holmquistite with a known reference. Ferro-ferri-holmquistite 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. Ferro-ferri-holmquistite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ferro-ferri-holmquistite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark violet, violet-blue, black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic to acicular crystals, fibrous aggregates.
Often confused with
Ferro-ferri-holmquistite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside ferro-ferri-holmquistite
Minerals reported to co-occur with ferro-ferri-holmquistite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- □{Li₂}{Fe²⁺₃Fe³⁺₂}(Si₈O₂₂)(OH)₂
- Mohs hardness
- 5-6
- Density
- 3.3-3.4 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic to Acicular Crystals, Fibrous Aggregates
- Cleavage
- Perfect On {110}
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Lithium-rich Pegmatites
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find ferro-ferri-holmquistite
Classic worldwide localities
- Sweden
- Canada
- Australia
- USA
Field-hunting tip
Look in lithium-rich pegmatites country — that is the host setting where ferro-ferri-holmquistite typically forms. If you start seeing spodumene, quartz, microcline in float, you are in the right ground. Field specimens usually show a prismatic to acicular crystals, fibrous aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ferro-ferri-holmquistite?+
Where is ferro-ferri-holmquistite found?+
How much is ferro-ferri-holmquistite worth?+
What rocks look like ferro-ferri-holmquistite?+
What minerals are found with ferro-ferri-holmquistite?+
What kind of rock does ferro-ferri-holmquistite form in?+
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Find ferro-ferri-holmquistite on the map
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