Harrisonite is an extremely rare calcium iron silicate phosphate found primarily in alkaline volcanic environments. Collectors typically look for its distinct, thin platy, metallic crystals that appear in association with other rare-earth bearing minerals. Due to its scarcity, it is almost exclusively found in professional mineral collections.
Is this harrisonite?
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 harrisonite with a known reference. Harrisonite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Harrisonite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Harrisonite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, brownish black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: platy crystals, tabular.
Often confused with
Harrisonite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Manaccanite is the harder of the two (Mohs 5-6 vs. 3.5); luster reads metallic on Harrisonite and submetallic on Manaccanite.
How to tell apart: Iron Ore is the harder of the two (Mohs 5-6.5 vs. 3.5); streak differs — Harrisonite leaves black, Iron Ore leaves reddish-brown to black; luster reads metallic on Harrisonite and metallic to submetallic on Iron Ore.
Often found alongside harrisonite
Minerals reported to co-occur with harrisonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaFe₆Si₂P₂O₁₆
- Mohs hardness
- 3.5
- Density
- 6.12 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Platy Crystals, Tabular
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find harrisonite
Classic worldwide localities
- Kola Peninsula, Russia
Field-hunting tip
Look in alkaline igneous rocks country — that is the host setting where harrisonite typically forms. If you start seeing magnetite, apatite, calcite in float, you are in the right ground. Field specimens usually show a platy crystals, tabular habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find harrisonite on the map
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