Stanĕkite is a rare iron-manganese phosphate mineral typically found as a secondary alteration product in granite pegmatites. It is often identified by its distinct black to dark brown massive habit and its association with other phosphate minerals in complex zones.
Is this stanĕkite?
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 stanĕkite with a known reference. Stanĕkite 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: dark brown.
- 3Read the lusterHold the specimen under a strong light. Luster: weakly submetallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral grains.
Often confused with
Stanĕkite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside stanĕkite
Minerals reported to co-occur with stanĕkite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe³⁺Mn²⁺(PO₄)O
- Mohs hardness
- 4-5
- Density
- 3.80 g/cm³
- Colors
- Streak
- Dark brown
- Luster
- Weakly submetallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral grains
- Cleavage
- Parting ⊥ [001]
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon alteration product of earlier phosphates in zoned complex granite pegmatites
Where rockhounds find stanĕkite
Classic worldwide localities
- Karibib, from the Clementine II pegmatite, Okatjimukuju Farm, and at the Helikon pegmatite, Namibia
- Cameroon pegmatite, Usakos, Namibia
- Albères massif, Pyrénées-Orientales, France
- Cap Creus, east of Figueras, Gerona Province, Spain
Field-hunting tip
Where it forms: An uncommon alteration product of earlier phosphates in zoned complex granite pegmatites. If you start seeing eosphorite, arrojadite, kryzhanovskite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify stanĕkite?+
Where is stanĕkite found?+
What rocks look like stanĕkite?+
What minerals are found with stanĕkite?+
What kind of rock does stanĕkite form in?+
What is stanĕkite used for?+
Find stanĕkite on the map
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