Matulaite is a rare phosphate mineral that typically forms as botryoidal or crust-like coatings in phosphate-rich localities. It is frequently associated with other secondary phosphate minerals like variscite and wavellite, often requiring magnification for accurate identification due to its small size.
Is this matulaite?
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 matulaite with a known reference. Matulaite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Matulaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Matulaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: botryoidal, crusts, radial aggregates.
Often confused with
Matulaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside matulaite
Minerals reported to co-occur with matulaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaAl₇(PO₄)₄(OH)₁₃·18H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.44 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Botryoidal, Crusts, Radial Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate Deposits in Hydrothermal or Weathering Environments
- Typical price
- $20-150 for micromounts or small specimens
Where rockhounds find matulaite
Classic worldwide localities
- Herd Mountain, Alabama, USA
- Hellertown, Pennsylvania, USA
Field-hunting tip
Look in phosphate deposits in hydrothermal or weathering environments country, the host setting where matulaite typically forms. If you start seeing variscite, wavellite, crandallite in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify matulaite?+
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Find matulaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
