Gatumbaite is a rare phosphate mineral typically found as delicate, radiating clusters of acicular crystals within phosphate-rich pegmatites. It was first identified in the Gatumba pegmatite field of Rwanda and remains a highly sought-after specimen for advanced phosphate mineral collectors.
Is this gatumbaite?
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 gatumbaite with a known reference. Gatumbaite 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. Gatumbaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Gatumbaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular or radiating clusters of prismatic crystals.
Often confused with
Gatumbaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside gatumbaite
Minerals reported to co-occur with gatumbaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaAl₂(PO₄)₂(OH)₂·H₂O
- Mohs hardness
- 3.5
- Density
- 2.44 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular or Radiating Clusters of Prismatic Crystals
- Cleavage
- Perfect in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find gatumbaite
Classic worldwide localities
- Gatumba district, Rwanda
- Sapucaia pegmatite, Brazil
Field-hunting tip
Look in granite pegmatites country — that is the host setting where gatumbaite typically forms. If you start seeing beryllonite, amblygonite, apatite in float, you are in the right ground. Field specimens usually show a acicular or radiating clusters of prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gatumbaite?+
Where is gatumbaite found?+
How much is gatumbaite worth?+
What rocks look like gatumbaite?+
What minerals are found with gatumbaite?+
What kind of rock does gatumbaite form in?+
What is gatumbaite used for?+
Find gatumbaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
