Gormanite is a rare hydrated iron aluminum phosphate mineral typically found as attractive sky-blue to deep blue bladed crystals. It is most famous for its occurrence in the phosphate deposits of the Big Fish River and Rapid Creek areas in the Yukon. Collectors primarily seek it for its vibrant blue color and its association with other rare phosphate species.
Is this gormanite?
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 gormanite with a known reference. Gormanite sits at Mohs 4-5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: blue green.
- 5Look at form & habitCrystal system: triclinic. Typical habit: aggregates, bladed, radial.
Often confused with
Gormanite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside gormanite
Minerals reported to co-occur with gormanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe²⁺₃Al₄(PO₄)₄(OH)₆·2H₂O
- Mohs hardness
- 4-5
- Density
- 3.10-3.13 g/cm³
- Colors
- Streak
- Pale green
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Triclinic
- Crystal habit
- Aggregates, bladed, radial
- Cleavage
- On {001}, poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As low-temperature fracture fillings in phosphate-ironstones (Yukon Territory, Canada); in fractures in tonalite (Bisbee, Arizona, USA)
Where rockhounds find gormanite
Classic worldwide localities
- Bisbee, Cochise Co., Arizona, USA
- G.E. Smith mine, Newport, Sullivan Co. and the Charles Davis pegmatite, Groton, Grafton Co., New Hampshire, USA
- Rapid Creek, Yukon Territory, Canada
- Tsaobismund pegmatite, 60 km south of Karibib, Namibia
Field-hunting tip
Where it forms: As low-temperature fracture fillings in phosphate-ironstones (Yukon Territory, Canada); in fractures in tonalite (Bisbee, Arizona, USA). If you start seeing souzalite, siderite, ludlamite in float, you are in the right ground. Typical habit: aggregates, bladed, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gormanite?+
Where is gormanite found?+
What rocks look like gormanite?+
What minerals are found with gormanite?+
What kind of rock does gormanite form in?+
What is gormanite used for?+
Find gormanite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
